有些名词只有复数形式，而且也只用作复数，如 :clothes ， glasses, spectacles ， pants ， arms( 武器 ) ， belongings( 所有物 ) ， customs( 海关 ) ， goods( 货物 ) ， suburbs( 郊区 ) ， papers( 文件 ) 等 ; 而有些名词形式为复数，却用作单数，如 :electronics( 电子学 ) ， mathematics( 数学 ) ， optics( 光学 ) ， politics ， statistics( 统计学 ) 等。例如 :
    The shorts he wears are made of leather.
    Linguistics is a difficult subject to study.
    He used to study electronics which isn't his favorite subject.
    I love to live in the suburbs that are conclusive.
     有些名词一般情况下以单数形式出现，表示总体。但如果表示若干、多次或几种时，则要用其复数。这类词有 :hair ， fruit ， pollution ， rain ， difficulty ， success ， wind ， failure 等。例如 :
    The barber had been cutting human hair for two years before he came to Los Angeles.
    Mother bought oranges ， bananas and other fruits.
    These caves collapse easily in heavy rains and great winds.
    He's having financial difficulties.
     有些名词一般只有单数形式，它们通常是表示物质和抽象概念的不可数名词，像 :advice ， baggage ， bread ， corn ， clothing ， equipment ， education ， fun ， furniture ， fruit ， garbage ， grass ， happiness ， homework ， housework ， humanity ， information ， knowledge ， landscape ， laughter ， machinery ， mankind ， merchandise ， money ， music ， nonsense ， nature ， population ， progress ， scenery ， smoke ， sweat ， strength ， traffic ， thunder ， ink ， jewellery ， damage ， mail ， work ， soap ， sugar ， gold ， chalk ， cloth ， anger ， applause ， cake ， chocolate ， poverty 等。例如 :
    I must seek the advice of a specialist in the matter of the transfer of property rights.
    Headache is the most common disease of human.
    I really get a lot of fun from reading in leisure time.
    The population of Shanghai is very big.
     有些名词单复数的含义不同，使用时要根据上下文的意思进行选择。这类词包括 :communication( 通讯 )-communications( 通讯系统，通讯工具 ) ， cloth( 布 )-clothes( 衣服 ) ， content( 内容 )-contents( 目录 ) ， convenience( 便利 )-conveniences( 便利设备 ) ， humanity( 人类 )-humanities( 人文科学 ) ， necessity( 需要 )-necessities( 必需品 ) ， wood( 木材 )-woods( 树林 ) ， pain( 疼痛 )-pains( 辛劳 ) ， ruin( 毁灭 )-ruins( 废墟，遗迹 ) ， sand( 沙子 )-sands( 沙滩 ) ， work( 工作 )-works( 工厂，著作 ) 等。例如 :     “Hometown” is one of Lu Xun's most famous works.
    The insurance company paid $121 ， 700 in damages for the accident.
    My child enjoys pIaying on the sands.
    No pains ， no gains.
     有些名词一般只有复数形式。如 :fundamentals( 基本原则 ) ， goods( 货物 ) ， means( 方法 ) ， shorts( 短裤 ) ， sweets( 欢乐 ) ， valuables( 贵重物品 ) 等。
    The fundamentals are made to guarantee the social stability.
    Don't take any valuables there for the sake of safety.
    The goods we purchased from him aren't expensive.
    I think our problem can solved by means of negotiation.
     名词做定语时，不能用作复数。例如 :
    Please check your examination paper carefully after finishing it.
    The China's Central Television station supplies weather report everyday.
    You'd better infom my family members before leaving for Beijing.
    The United States and Germany are two member states of NATO .
     复合名词的复数只把其中所包含的主体名词变成复数。如 :looker(s)-on ， runner(s)-up ，
    son(s)-in-law ， editor(s)-in-chief ， passer(s)-by ， grand-child(ren) ， armyman(armymen) ，
    room-number(s) ， shoe lace(s) ， dinner plate(s) ， blood type(s) 等。如果没有主体名词，就在最后一个词上加复数词尾。如 :go-between(s) ， drawback(s) 等。注意以 man ， woman 构成的复合名词，全部变成复数。如 :man-servant---men-servants ， woman-soldier---women-soldiers 。例如 :
    Would you bring me some dinner plates?
    We had a wonderful talk with some women-soldiers.
    Don't regard yourselves as passers-by under such circumstances.

    We are of different blood types.
     名词的所有格一般在词尾加 's ，已有复数词尾 -s 的，只加 ' 。例如 :
    We must work hard to fulfil the country's plans.
    The school is within a stone's throw .
    Nearby are her relative' houses.
     Could you tell me the Smith's address?
     名词所有格有时还可以和 of 构成短语，有以下两种情况 :
    1) 它所修饰的词前面有一个表示数量的词，如 :a ， two ， several ， some ， any ， no ， few 等。
    2) 它所修饰的词前面有一个指示代词，便句子表示某种情绪。例如 :
    Several students of Lao Yang's acted in the play.
    We saw a play of Guo Moro's
    At birth ， the head of a baby is extremely large in relation to the rest of the body.
    I have some records of Na Ying's. 以上是名词的用法。
    2. 代词的用法
    1) 人称代词有主格人称代词，在句中充当主语 :I ， you ， he ， she ， it ， we ， you ， they ，和宾格人称代词，在句中充当宾语 :me ， you ， him ， her ， it ， us ， you ， them 。例如 :
    We haven't seen each other for a long time since he went abroad.
    Let you and me have an appointment for the next weekend.
    Have you got any idea about this issue?
    Tell us whatever you've heard.
    2) 物主代词可在句中作定语，有指人的 :my ， our ， your ， his ， her 和 their; 有指物的 :its ， his 或 her( 指国家或轮船 ) 。名词性物主代词作表语、主语、宾语，与 of 连用可作定语 :yours ， ours ， theirs ， mine ， her ， his ， its 。例如 :
    Tonny is an old friend of mine.
    My dormitory is next to yours, and Mary's is on the third floor.
    Titanic sank with her several thousand passengers.
    Next time it's on my treat.
    3) 反身代词亦称自身代词，可作宾语、表语，作主语或宾语的同位语，还与某些动词连用，与介词连用构成成语。有 :myself ， yourself ， himself ， herself ， itself ， ourselves ， yourselves ， themselves 。例如 :
    These Children are too young to take care of themselves.
    Don't worry ， he will be himself again soon.
    Although Uncle George is a bad-tempered man, I think he is a kind man in himself.
    You should be responsible for yourself.
    4) 相互代词表示相互关系，有 :each other( 两者之间 ) 和 one another( 多者之间 ) 。例如 :
    I met Miss Scott this morning ， and We greeted each other.
    We should learn from One another and make progress together.
    5) 指示代词在句中充当主语、宾语和定语，有 :this ， that ， these ， those 。 Such 也是指示代词，可作定语、主语和表语，修饰可数名词时要与 a 连用。例如 :
    Nowadays TV programs are much more colorful than those of the past.
    The money spent on entertainment ， according to some authorities ， has exceeded that spent on public health.
    I want to know this: are you talking about the accident I enountered yesterday?
    His future is closely bound with that of the company.
    You shouldn't trust on such a person who never keeps his promise.

6) 疑问代词有 who ， whom ， whose ， what ， which 。 who 可作主语和表语， whom 作宾语， whose ， what ， which 可作主语、表语、宾语和定语，其中作主语时，要看所代表的人或物是单数还是复数，如果不清楚，则动词一般用单数。
    Who will see to this matter?
    Whom have you chosen to be responsible for the work?
    It is hard to decide whose is better.
    What's on your schedule?
    Which university did he enter at last?
    7) 关系代词有 who ， whom ， whose ， that ， which 。 which 代表事物， that 代表人或物；在非限制性定语从句中，不能用 that ，而用 who(m ) 代表人，用 which 代表物，或代表主句所说的全部内容。在带有 all ， something ， nothing ， anything ， much 等的句子中不能用 which ，而用 that 。例如 :
    Our football team was defeated again ， which shows our players need much more effort.
    The factory now has over l,000 workers ， half of whom are women.
    He promised to tell us all that he knew .
    Whose turn to make presentation is beyond me.
    8 连接代词有 :what ， who ， whom ， whose ， which ，用来连接主语从句、宾语从句和表语从句。 Whoever ， whomever ， whichever ， whatever 为复合代词。例如 :
    I didn't know what to do at that very moment.
    The government sells public houses to whoever provides enough amount of money.
    Whomever I worry about is none of your business.
    Take whichever you like ， please.
形容词与副词
     形容词与副词在语法结构上都有比较级和最高级，它们的构成方法基本上一样，都与音节多少有关，有些形容词相副词有特殊的比较级和最高级形式。二者基本分为同级比较、比较级和最高级三种形式。
    1. 形容词与副词的用法
    l   形容词中有词形相近的，应注意区别。如 :
considerate( 周到的，体贴的 )--considerable( 应考虑的 ) 　　例如 :
    We did enjoy our staying in Beijing ， and Mrs. Yan is really considerate Professor.     It's a considerable success for him. eminent( 闻名的 )--imminent( 紧迫的 ) ， gracious( 亲切的 )--graceful( 优雅的 ) ，live( 有生命的 )--aIive( 活的 ) ， industrious( 勤劳的 )--industriaI( 工业的 ) ， like( 同样的 )--alike( 同样的，仅作表语 ) ， opposite( 相对的 )--opposing( 反对的 ) ， perspective( 透视的 )--respective( 各自的 ) ， sensitive( 伤感的 )--sensible( 明显的 ) ， etc 。
    2)   形容词中有的词义相近的，也要注意。如
elemental( 初步的 )--fundamental( 基本的 ),eligible( 合格的 )--capable( 能干的 ) ，    flexible( 灵活的 )--changeable( 可改变的 ) ， initial( 最初的 )--preliminary( 初步的，预备的 ) ， slack( 松弛的 )--lazy( 懒惰的 ) ， vaIueless( 无价值的 )--priceless( 无价的 ) ， vivid( 生动的 )--living( 活的 ) ， etc 。
　　例如 :
    Henry's speech was so vivid that his audience applauded again and again.
    It is easier adapt to new situation if one has a flexible attitude. We have finished the preliminary exam .
    Your suggestion is priceless ， and I will consider it carefully.
    3) 有些词尾为 -ly 的并非副词，而是形容词 , 如 :lovely ， likey ， deadly ， earthly( 现世的 ) ，  leisudy( 空闲的 ) ， weekly ， yearly ， manly( 丈夫气概的 ) ， brotherly ， friendly 等。例如 :
    What a lovely girl! Jenny is always ready to help others.
    China Daily is of course a daily newspaper but not a weekly one. He is a very friendly young man. As he didn't have any experience ， he was likely to have problems.
     以下情况形容词常用于 后置 :1) 形容词短语，即形容词十副词，介词短语或不定式。 2) 一些表语性形容词要后置，如 :present ， available ， involved ， concerned ， etc 。 3) 形容词修饰不定代词 something ， anything ， everything 时要后置。例如 :
    There was something nice about my feeling that she knew all.
    I came across another question hard to answer then .
    I wondered if there was a room available.
      副词的位置 为 : 修饰哪个词就放在哪个词前面 ; 放在系动词和助动词之后，行为动词和分词之前。例如     I had a only five-dollar bill with me when I boarded the townward train.
    The old law was instituted to protect the long neglected rights of children.
    I can hardly believe that he is the murderer.
    Although he has advantages ， it is still too early to say that he is sure to win.
    2. 比较级与最高级的基本形式和用法
     形容词的比较级和最高级的构成为 : 单音节词一般在词尾加 -er 和 -est 。 如果以 -e 结尾，仅加 -r 和 -st; 　　如末尾仅有一个辅音字母，须双写词尾再加 -er 和 -est; 如果以 y 结尾的，把 y 变 i ，加 -er ， -est; 多音节单词和双音节词 ( 其中包括由分词和分词演变而来的形容词，如 :known ， worn ， wounded ， shocking ， striking ， interesting ， e.ct. 则在其前加 more 和 most; 有些形容词的比较级和最高级是不规则的，如 :good(well)-better-best ， bad(ill)-worse-worst ， many(much)-more-most ， little-less-least ， far-farther(further)-farthest(furthest) 。
有些形容词没有比较级形式，如 :absolute ， chief ， entire ， eternal ， excellent ， fatal ， final ， foremost ， inevitable ， infinite ， main ， naked ， perfect ， possible ， primary ， right ， sufficient ， supreme ， universal ， utter ， vital ， whole ， wooden ， ect. 例如 :
    Mary is the best student in the class.
     Further negotiation will be conducted next month.
    The food we have is sufficient .
    Needless to say ， he is stronger than his opponent.
     一般副词的比较级和最高级与形容词一样，单音节的以在词尾加 -er 和 -est 构成，多音节的以加 more 和 most 的方法构成 ; 有些比较特殊 , 如： well-better-best ， badly-worse-worst ， much-more-most ， little-less-least 。以 -ly 结尾的副词，在其前面加 more ， most 。例如 :
    Tonny runs more beautiful than any other students in the class.
    Which do you like best ， Thorn Birds ， Gone With the wind or great expectation?
    I prefer less sugar in the milk.
    She get more income every month than her husband.
     形容词和副词的原级比较由 “as + 形容词或副词 ( 或后跟名词或短语 )+as” 构成， “as-as“ 前可加 not ， just ， almost ， nearly ， quite ， twice ， several times 等词修饰。否定式中 not 后面的 as 可改为 so 。例如 :”
    Running for fifteen minutes will burn as much calories as walking for thirty minutes.
    Henan Province is several times as large as shanghai.
    Jimmy has as nervous a way of speaking as his father.
    Getting rid of a bad habit isn't so simple as taking it up.
     形容词与副词的比较级形式为 :“ 形容词 ( 副词 ) 比较级 +than+-” ，应注意 than 前后相比较的人或物要一致。比较级前可以跟 even ， much ， stilI 等副词修饰比较级，表示强调。例如 :
    Mother worried much more about my younger brother than she did about me.
    Sound travels faster through water than through air.
    The economic development in south China is faster than that in North China .
    My books are much more than Li ping's.
     形容词与副词的最高级的形式分别为 :“the+ 形容词最高级 + 名词十范围表达 ” 和 “ 副词最高级十名词 + 范围表达 ” ，副词的比较级和最高级不需要加 the 。例如 :
    Our foreign exchange reserve didn't decline despite the worst flood in sixty years.
    I finished the work more successfully than he had expected.
     应注意以下表达式的含义 :the same as( 和 …… 一样 ) ， no less than( 不少于 ) ， not less than( 只有 ) ， had better( 最好 ) ， less than( 不到 ) ， more or less( 或多或少 ) ， other than( 除了 ) ， rather than( 而不是 ) ， the more…the more/less( 越 …… 就越 ……)
例如 :I am sure that the amount of money used in repaying a loan would have the same value as the amount of money borrowed.
    You had better finish your homework today for the teacher will collect it tomorrow .
    We have received ten dozen of personal computers which are less than the amount we ordered.
    The visitors to the exhibition were not less than three hundred, which disappointed them very much.
时态与语态
1. 时态
　　现在完成时表示过去某时开始的一个动作或状态一直延续到现在，表示现刻以前发生的动作或情况。常用状语 just, since, for, already, yet, ever, never, often,  several times, lately, recently, during the last week, so far, up to now(the present) 等，由 since 引起短语（或从句）的句子里，主句的谓语应用完成时；若 since 引起一个从句，从句谓语可用过去时（表示行为的起点）。只有在 “it is ……since” 的句型中，主句才可用也可不用完成时。例如：
　　Japanese is certainly difficult for me as I have never learned it before.
　　We are living a hard life because Father has been unemployed for half a year.
　　I have planted thirty trees since I moved here.
　　现在完成时与过去时的比较：现在完成时表示某一动作一直延续到现在或已经完成，强调结果；而过去时表示发生在过去的动作，强调过去的动作。例如：
　　He has read the book for two hours.( 强调动作的持续 )
　　He has read the book.（强调动作的完成）
　　He read the book last night. （强调过去的动作，有过去时间状语）
　　过去完成时表示在过去某一时刻或某一动作之前已完成的动作。例如：
　　I still remember last summer vacation spent in Paris. That was the first time I had ever been to Europe.
　　Since he had eaten before he came to the party, he refused the hostess ' s offer of a cake.
　　将来完成时表示将来某一时间之前已经完成的动作，分为一般将来完成时和过去将来完成时。常用 by the time, at the end of 来引起。例如：
　　The debate will have begun by the time our English teacher arrives.
　　Tonny bad thought the train would have left by the time he got to the station.
　　At the end of next month, I will have finished this work.
　　现在完成进行时强调过去发生的动作一直延续到说话时刚结束，或动作仍在进行中。过去完成进行时表示动作延续到某一时间刚结束，或仍在进行。例如：
　　Eventually, I received the letter that I had been expecting for a long time.
　　When she retires, Mrs.Jones will have been teaching here for over thirty years, but her classes are never dull.
2. 语态
　　英语分为主动词态和被动词态。主动语态是指句中的主语是动作的执行者，而被动语态的主语是动作的承受者。英语中只有及物动词、动词短词和某些成语才能构成被动语态。被动语态的构成形式为 “be+ 动词的 -ed 分词 ” 。另外， “be+get+ 动词 -ed 分词 ” 是特殊形式。
　　1 ）动词的被动语态有以下几种时态的变化（以 find 为例：）
　　 现在时： is (are)found      将来时： shall (will)be found      现在进行时： is (are)being found
     现在完成时： have (has)been found      将来完成时： shall (will)have been found      过去时： was (were)found
     过去将来时： should (would)be found      过去进行时： was (were)being found      过去完成时： had been found      过去将来完成时： should (would)have been found
     例：     Mineral water has been regarded by all people as a healthy drink.
    The program bad been conducted in both the United States and Europe well before 1900.
    2 ）能作及物动词的短语动词也可用被动态，应注意其固定搭配。例如：
    The problem will be taken care of as soon as possible.
    Although the mission was to be kept a secret, it was revealed to the press.
    3 ）表示状态或特征的及物动词，如 :contain, cost, fit, have, lack, suit 等；不及物动词及动词短语，如： result from, belong to, consist of 等，不能用被动态。例如：
    The magazine that I bought the day before yesterday costs me twenty and a half yuan.
    Some critics maintain that when a work of literature lacks reference to the general experience of mankind, it fails as art.

从句
　　从句分为定语从句，状语从句和名词从句三大类。定语从句又分为限定性和非限定性从句两种，由关系代词或关系副词引导，修饰主句的某个成分。状语从句分为时间、结果、让步原因、条件及行为方式状语从句。名词从句包括主语、宾语、表语和同位语从句及 there be 句型。
1. 定语从句
　　限定性定语从句中 that 可代表人和事，而 which 只代表事；二者在从句中作主语或宾语。 that 作宾语时常可省略， which 则不能，而且其后的 “ 不及物动词 + 介词 ” 中的介词不能省略。 which 作宾语时，先行词与 which 之间的介词不能省。例如：
　　The first doll that could say “mama”was invented in 1830.
    The second half of his voyage was by far the more dangerous part, during （不能省） which he sailed round the Cape Horn.
     代表 all, anything, something, nothing, much 等词时，用 that 而不用 which ， that 作宾语可省略。例如：
    You'd better do something he prefers to do to please him.
    That is the last time we met each other.
    I came across the woman you told me about yesterday.
    who 和 whom 引导的从句用来修饰人，分别作从句的主语和宾语。 where 是关系副词，用于表示地点的定语从句，而 when 用来表示时间。 whose 是关系代词，修饰名词作定语。例如：
    Henrey Ford is the person who is most responsible for developing the idea of mass production.
    The knee is the joint where the thigh bone meets the large bone of the lower leg.
    The next morning when she came down to breakfast, Mary was beaming with the pleasure ( 眉飞色舞 , 笑逐颜开 )of a new, great discovery.
    The visiting professor is a famous scientist whose son studies in my department.
  在下列情况，限定性定语从句的关系代词可以省略； 1 ）当关系代词在从句中作宾语或表语；或它们在从句中作介词的宾词，而该介词又在句末时； 2 ）当先行词是 that, all, only, everything, something, nothing 等代词时，或先行词前有一个最高级形容词修饰时； 3 ）当先行词前有 only, any, all, first, no, last 等修饰时，或先行词就是 time, moment, way(any-way) direction, distance 等名词时，关系代词即可省略。例如：
    The delegation we has been waiting for finally arrived
    I met the woman you told me about.
    She gave me all she could afford.
    With TV we can see things happen almost at the exact moment they are happening.
     非限定性定语从句，其作用为：对所修饰的成分作进一步的说明，它与主句用逗号隔开。此类从句省略后其余部分仍可成立。在非限定性定语从句中， which 可代表前面的整个句子；代表人时只能用 who, whom, 而不能用 that; as 也可用作关系代词。例如：
    The telephone, as we know, was the invention of Alexander Graham Bell.
    The Little White House in Warm Springs was the Georgia home of President Franklin D.Roosevelt, who died there on April 12,1945.
    Living in a damp house for a long time is harmful to one's health, which is known to everyone.
    2. 状语从句
     状语从句可分为：时间状语从句（主要由 when, whenever, after, before, as, since, once, as soon as, until, while ）  so……that such……that   though, although, no matter, even if however, whatever  as, because, since  for  is, whether, as long as, provided that where  as
    The small greenish flowers of the elm tree appear in the spring, long before the leaves grow.
    Qiong Yao's novels used to be so popular that her books appeared on best seller lists.
    Gas balloon is less safe than hot balloon because it may catch fire.
    Uniform acceleration( 同样的加速 )occurs if the rate of change remains the same over successive equal intervals of time.
    Thousands of Chinese college students went to the US Consulate in Shanghai, where they protested NATO's bombing at China's Embassy in Yugoslavia.
     状语从句的中 “ 主语 +be” 可以省略，前提是，从句主语和主句主语一致，且从句谓语 “be” 省略后的结构为 “ 连词 + 现在分词 / 过去分词 / 介词短词 / 形容词 / 名词短语 ” 。例如：
    When well fitted ， glasses can correct most sight defects in healthy eyes.
    If necessary, I would like to see you in your office.
    Although seriously wounded, he never complained
    3. 名词从句
     名词从名包括主语从句、宾语从句，其中有介词与形容词的宾语从句、表语从句和同位语从句。
    1 ）主语从句
     主语从句常出现在 “it is + 名词、形容词、分词 + 主语从句 ” 的形式中。例如：
    It is reported that Taiwanese pop singer Meng Tingwei will hold a solo concert in Shanghai someday this month.
    It must be pointed out that you have failed to meet the deadline.
    It usually happened that I was late because of traffic jams.
     主语从句还可用 when, where, how, why, whether 等连接副词，和 who ， whom ， whose ， what ， which ， whoever ， whatever ， whichever 等连接代词来引起。例如：
    How to arrange the meeting is not your task.
    Whose candidate will win the election is the question both political parties are asking.
    When I leave is my own decision.
    Whoever will go to the party won't change my mind of staying at home.
    2 ）宾语从句
     宾语从句可由 that, 疑问代词或副词 how, why 和 where 等引出。例如：
    To postpone the conference until next month indicated that they were unprepared.
    Nearly all the staff agreed with what I said.

    Everyone worried about her because no one was aware of where she had gone.
    Could you offer more details except that it happened at night?
     由 what, whether, how 引导的宾语从句可用在介词后，而由 that 引导的从句只跟 but, besides, except, in, save 之后。例如：
    I can hardly believe in what they have done.
    He doesn't know my phone number except that the city code is 021.
     一些表语性的形容词，如： alarmed, amazed, annoyed, astonished, certain, confident, disappointed, glad, pleased, proud, sad, shocked, sure, surprised, worried, ect. 作表语时，后面可跟由 that, how 等引导的宾语从句。例如：
    I was amazed how he could pass the exam without attending the lectures.
    He is confident that he will pass the Band 6 examination.
    She was surprised how simple his problem was.
    We are all pleased that he will be able to pass the final examination.
    3 ）表语从句
     表语从句对主语的内容起解释和阐述的作用；若表语从句用 that 引起， that 起连接作用，不能省略。表语从句也可用连接词 how, when, where, why, what 引起。由  because 引起的表语从句通常只用在 “this/that/it is because” 结构中。例如：
     On thing I admire most about them is that they are hospitable.
    She works too hard. That is why she is exhausted.
    I must point out that where you intend to build a super-market is where the elderly do exercise everyday.
    4 ）同位语从句
     同位语从句是由两个或两上以上同一层次语言单位组成的结构，其中前项与后项所指相同，句法功能相同。同位词从句由 that 引导，也可由 whether, how, why,  where, when 等来引导。例如：
    She ignored the teacher's instruction that she must study hard.
    The question whether or not I should help him in such a case troubled me greatly.
动词不定式
    1. 不定式的基本形式与结构
     动词不定式指通常由 to 加上动词原形（如 ro write ）所构成的一种非限定性动词形式，但在有些情况下 to 可以省略。动词不定式有进行体和完成体（如 to be writing, to have written ）也有被动态（如 to be write ），所有的主动词，不论是及物动词还是不及物动词，也不论是动作动词还是状态动词，都有不定式形态。助动词除 be 和 have 外，没有不定式形式。动词不定式在语法功能上可作主语、宾语、表语、定语和状语。
    2. 不定式的用法
    1 ）不定式结构作主语
     To get contact with family in Taiwan made him extremely happy since they separated more than 40 years ago.
     To finish that task in such a short time is really a challenge.
     在上述情况下，如果不定式较长，显得头重脚轻，则可由代词 it 作形式主语（形式主语 it 不可由 that 或 this 等其他代词代替），而将不定式放在后面。如：
    It made him extremaly happy to get contact with his family in Taiwan since they separated more than 40 years ago.
    John admitted that it is always difficult for him to be on time.
     不定式结构所表示的动作是谁做的，即不定式的逻辑主语，通常可以通过 for sb.to do sth. 结构表达。
    It is quite important for us to read good books during a general review.
    It is not difficult f or those talented students to pass the exam.
     在某些形容词（如： careless, clever, considerate, foolish, good, impolite, kind, naughty, nice, silly, stupid 等）作表语时，不定式后可以加 of 来引导出其逻辑主语：
    It is very kind of you to tell me the truth.
    It is stupid of him to do such a silly thing.
    2 ）不定式作宾语
     不定式作宾语有两种：一种是及物动词后直接跟带 to 的不定式，另一种是 “ 及物动词 + 疑问句 + 带 to 的不定式 ” 。
     及物动词 + 带 to 的不定式结构：      只能跟动词不定式的动词，常见的有：
afford, agree, aim, appear, ask, believe,?care, claim, ecide, demand,desire, determine, expect, fail, happen, hesitate, hope, intend, learn, long, manage, offer, pretend,promise, prepare, refuse,seek, sweat,
undertake,want,wish 等。（须记住）    He managed to solve the complicated problem
    The stranger offered to show me the way.
    Mr.Smith undertook to build a new plant in South Africa.
     动词 + 疑问代（副）词 + 不定式：这类动词常见的有： advise, decide, discuss, find out, forget, inquire ,know, learn, regard, remember, see, teach, tell, understand, wonder 等。常用的疑问代（副）词有 what, when, where, which, how, whether 等，但不包括 why 。
    He does not know when to start.
    You can decide whether to continue or to stop.
    I will show you how to deal with it.
     有时，不定式可由 it 代替，而把不定式放到后面去。这可以用这一结构表达：动词（如 find, think, consider, feel 等） +it+ 形容词 + 不定式。
    She considers it necessary to make friends with them.
    We find it difficult to finish all the homework before 9 o'clock.
   3 ）不定式作表语
     一般情况为主语是不定式（表示条件），表词也是不定式（表示结果）：
    To see is to believe.     To work means to earn a living.
     另一种情况为主语是 aim, duty, hope, idea, job, plan, problem, purpose, thing, wish 等名词为中心的短语，或以 what 引导的名词性从句，不定式表语对主语起补充说明作用：
    His aim is to study abroad in the near future.
    The most important thing is to negotiate with them about the problem.
     What I want to say is to forget all the unhappy experience.
    4 ）不定式作定语
     不定式结构作名词词组修饰语主要有三种类型：
     第一种，被修饰的名词词组是不定式的逻辑宾语。例如：
    There was really nothing to fear.     He gave me an interesting book to read.
     如果不定式是不及物动词，后面就得加相应的介词。例如：
    Mary needs a friend to play with.     That girl has nothing to worry about.
    They have a strict teacher to listen to .
    Although the film had been on for ten minutes, I still was not able to find a chair to sit on.
     第二种，被修饰的名词词组是不定式的逻辑主语。例如：
    Have you got a key to unlock door?
    The action to be taken is correct.
    There is nothing to be gained by pretending.
     第三种，被修饰的名词词组是不定式的同位结构。这类名词通常是表示企图、努力、倾向、目的、愿望、打算、能力、意向等意义的名词，如 ability, attempt, effort, impulse, inclination, wish 等。例如：
    Her daughter will make an even bigger effort to please her.
    I have no wish to quarrel with you.
    Neither of them had any inclination to do business with Mary.
     （ 5 ）不定式作状语
     不定式结构在句中作状语通常都能转换为限制性状语从句。例如作原因状语：
    They are quite surprised to see the great changes taking place in the area.
    =They are quite surprised because they see the great changes taking place in the area.
    He was lucky to arrive before dark.
     作目的状语：
    She raised her voice to be heard better.   =She raised her voice so that she could be heard better.
    We went via Heidelberg to miss the traffic jam.
    =We went via Heidelberg so that we could miss the fraffic jam.
     作结果状语：
    The French football team played so successfully that they even defeated the Brazilians.
    He got to the station only to be told the train had gone.
    =He got to the station and was told that the train had gone.
    3. 不带 to 的不定式的使用
     动词不定式通常带 to ，但有些搭配中不带 to ，在另一些搭配中可带 to 可不带 to 。归纳起来，以下情况下使用不带 to 不定式：
    1 ）在 can/could, may/might, will/would, shall/should, must, need, dare 等情态动词之后，动词不定式不带 to 。
    2 ）在表示感觉意义的动词，如 see, feel, watch, notice, smell, hear, observe 等后，或是表示 “ 致使 ” 意义的动词，如 have, let, make 等后，动词不定式不带 to 。例如： I often heard him say that he would study hard.
    I must have him see his own mistakes.
     但是，当这类结构转移为被动语态时，后面的不带 to 不定式一般转换为带 to 不定式。
     例如：     He was often heard to say that be would study hard.
    After he had finished the speaking, he was made to answer innumerable questions.
    3 ）在动词 help 之后可用不带 to 和不定式，也可用带 to 的不定式。例如：
    help the old lady(to)carry the heavy box.
    4 ）在 had better, would rather, may/might as well, rather than, cannot but 等搭配之后，动词不定式也不带 to 。例如：
    Unless you feel too ill to go out, I would rather not stay at home tonight.
    She could not but criticize his foolish behaviour.
    5 ）在 make do, make believe, let drop, let fall, let fly, let slip, let drive, let go off, hear, say, hear tell, leave go of 等固定搭配中，用不带 to 的动词不定式。例如：
    They let go off the rope 。他们松开了绳子。
    John let fly a torrent of abuse at me 。约翰朝我痛骂了一顿。
    I've heard tell of him 。我听说过他。
    Some of the faculty were let go for lack of the students. 由于生源不足，一些教职员工被解雇了。
    6 ）在介词 but, except 之后，如果其前有动词 do 的某种形式，其后不定式一般不带 to ，反之则必须带 to ，表示 “ 不得不，只能 ” 。例如：
    He will do anything except work on the farm.
    There was nothing left for the enemy to do but surrender.
    The spy was both hungry and cold; there was nothing left for him but to give in.
    I had no choice but to wait till it stopped raining.
     下面一些短语是固定搭配，不带 to ：
    can not help but, can not choose but, can not but, do nothing but, have nothing to do but 。例如：
    I can not but admire his courage.
     如果上述句中有 do ， to 省略：
    I did nothing but watch TV last night.
      如果是下面一个固定搭配，就带 to ：
    I have no choice but to give up my idea.
7 ）紧跟在 why 或 why not 之后的动词不定式总是不带 to 。但是，紧跟 who, what,
    which, whether 等连接词后的不定式带 to 。例如：
    Why stand up if you can sit down?
    Why not ask your teacher when you don't understand the meaning?
    You needn ' t decide yet whether to study arts or science.
    4 不定式的完成式和进行式
    1 ）构成
     完成式： to+have done
     进行式： to+be doing
    2 ）用法
     完成式：如果不定式所表示的动作（状态）发生在主要谓语动作之前，那么不定式就要用其完成式。
     进行式：如果主要谓语动作（情况）发生时，不定式所表示的动作正在发生，那么不定式就要用其进行式。例如：     She feels relaxed to have finished writing her thesis before the deadline.
    The Vikings are believed to have discovered America.
    When you called me last night, I happened to be working on the computer.
    5. 不定式的被动形式
     当不定式的逻辑主语是动作的承受者时，不定式要用被动形式，包括它的一般式和完成式。例如：
        The snow was supposed to have blown off the mountain.
    6. 不定式的否定形式
     否定形式是在不定式的标志 to 前加 not 。例如：
    I decided not to ask him again.
    Please remember not to leave the lights on when are out.
动名词
1. 动名词的形式
　　动名词是由动词原形 +-ing 构成（如 writing) ，有完成时态和被动语态（如 having written, being written) 。
2. 动名词的用法
　　动名词通常在句中作主语和宾语。
　　1 ）动名词作主语
　　Going to the college is the little boy's dream.
　　Keeping studying hard will make you pass the exam.
　　2 ）动名词作宾语
　　有些动词后面只能带动名词作宾语，不能带不定式作宾语。此类动词常见的有： admit, acknowledge, anticipate, appreciate, avoid, consider ,contemplate,  defer, delay, deny, detest, dislike ,ensure, enjoy, escape, excuse, evade, facilitate, fancy, favour, finish, forbid, imagine, include, keep, mind, miss, postpone, practise, resent, resist, risk, suggest, quit, worth 等。例如：
　　John was considering buying a new car.
　　I hope you didn't contemplate coming with us on this trip.
　　The witness denied having seen the accused man.
　　I would appreciate your keeping it a secret.
　　3) 某些短语后面只能接动名词，不能接不定式。
　　此类短语常见的有： be(get)used to be accustomed to, be dedicated to, be devoted to, be busy, be committed to, be subject to, cannot help, cannot resist, cannot stand, confess to, feel like, give up, have trouble(in), have difficulty(in), have a good/have time(in), have fun(in), have an objection to, it is no good/use, keep on, insist on, look forward to, object to , pay attention to, put off, resort to, succeed in 等。例如：
    I cannot stand getting up early in the morning.
    I have no difficulty(in) reaching the top of the mountain.
     There is no use staying on.
    I cannot resist (his)bargaining.
    Although punctual himself, the professor was quite used to students' being late for his lecture.
    4 ）动词或短语后面也可以接动名词的被动形式。用主动形式还是被动形式，要根据包子的意思而定。例如：
    Carlos just missed being caught.
    That person wore dark glasses to avoid being recognized.
    I object to being treated like a child.
    3. 另一类动词后面可以带动名词作宾语，也可以带不定式作宾语。这类动词又可以分为两种：
    1 ）带动名词作宾语与带不定式作宾语而意义无多大区别的动词
    a ）在 begin, cannot bear, cease, continue, dread, like, love, neglect, omit, propose 等动词之后，如表示一般的行为，用动名词作宾语为多；如表示特定的或具体的动作，则不定式结构作宾语为多。例如：
    I don't like swimming.
    I don't like to swim this afternoon.
    John prefers doing it his way.
    John prefers to go outing tomorrow.
    b ）在 begin, start 等动词之后，如表示有意的动作，用动名词结构为多；如表示特定的或具体的动作，则用不定式结构作宾语为多。例如：
    After some hesitation, he began speaking out his own opinion.
    It has already begun to rain.
    c ）在 attempt, intend, plan 等动词之后，用不定式结构与动名词结构意义相同，但以用不定式较为常见。例如：
    He intended to buy a new car.
    He intended travelling abroad next summer.
    d ）在 encourage, permit, allow, recommend, advise, authorise 等动词之后，一般用动名词作宾语，或者用不定式作宾语补足语。即：
    encourage/permit/allow/recommend/advise/
authorise+doing,encourage/permit/allow/recommend/
advise/authorise+somebody+to do
     例如：
    He advised going out for a walk.
    He advised us to go out for a walk.
    e ）在 agree, decide 等动词之后，可以直接跟不定式结构， 但如果跟动名词，则动词后必须加适当的介词。例如：
    In the end the manager decided to double the advertising budget.
    =In the end the manager decided on doubling the advertising budget.
    f ）在 need, want, require, deserve 等动词之后，可以用 动名词的主动形式表示被动 意义，这相当于不定式的被动形式。例如：
    The house needs repairing.
    =The house needs to be erpaired.
    The disabled deserve respecting.
    =The disabled decerve to be respected.
    2 ）带动名词作宾语与带不定式作宾语而意义不同的动词
    a ）动词 remember, forget 后可以跟不定式或动名词，但意义有明显区别：跟动名词，其动作发生在 “ 记得 ” 或 “ 忘记 ” 的动作之前；跟不定式，其动作发生在 “ 记得 ” 或 “ 忘记 ” 的动作之后。试比较：
    I remember posting this letter. 我记得这封信已寄出了。
    I remember to post this letter in the afternoon. 我记得下午要将这封信寄走。
    b ）动词 regret 后可以跟不定式或动名词，但意义有明显区别：
    regret doing: 为做过的事感到抱歉
    regret to do ：为即将要做的事感到抱歉
     试比较：     I regret to say that I can not go with you after school.
    I regret having criticised you seriously in class.
    c ）动词 try, mean, cannot help, used to 后跟不定式还是动名词，取决于这些词本身的含义。例如：
    You should try to answer the questions by yourself.(Try to d 试着做某事 )
    We try using this new method.(Try doing ：试着做某事 )
    I meant to go to the exhibition but I forgot(mean to do ：打算做某事 )
    Success means working very hard.(mean doing: 意味着做某事 )
    I can't help apologizing.(cannot help doing: 忍不住做某事 )
    I can't help to apologize for him.(cannot help to d 不能帮助做某事 )
    Mr.Smith used to jog in the morning, but now he has stopped.(used to d 过去经常或总是干某事 )
    Inland canals are used to ship farm and factory goods to nearby towns.(be used to d 被用来干某事 )
    I am not used to getting up early in the morning.(be/get used to doing: 惯于干某事 )
    d ）动词 stop, continue, go on, leave off 之后，通常用动名词结构作宾语，如果用不定式结构，则不是宾语而是目的状语，相当于 in order to 。试比较：
    They stopped working 。他们停止工作（来做其他事）。
    They stopped to work 。他们停止（帮其他事）来工作。
    The students went on reciting the text. 学生们继续背诵课文。
    The students went on to recite the text. 学生们停下其他事，继续背诵课文。
    She left off doing the housework. 她停止做家务（去干其他事）。
    She left off to do the housework. 她停止（干其他事）来做家务。
4. 动名词的逻辑主语问题
     动名词，顾名思义，具有名词的特点，即可以加物主代词和名词的属格来表示其逻辑主语（这时动名词的逻辑主语与句子主语不一致）。如果动名词的逻辑主语就是句子主语，则前面不用加物主代词或名词的属格。例如：    The watchman reported finding the door open.
    =The watchman reported that he had found the door open.
     此外， finding 的主语与主句主语一致，都是 the watchman ，所以 finding 前不加物主代词。
    I appreciated very much your helping me through the tough period.
     此处， helping 的主语是 you ，而主语是 I ，两者不一致，所以 helping 前的物主代词 your 不能省略。
     一般说来，能带动名词作宾语的动词都可以根据语义意图在动名词之前加上或略去逻辑主语。但有些动词，如 excuse, forgive, pardon 等，其后的动名词结构总是带有逻辑主语的。这些逻辑主语通常由名词或代词宾格表示，也可由名词属格或形容词性物主代词表示。例如：
    I do mind people smoking in public places. （名词宾格作逻辑主语）
    We don't understand him needing so much money. （代词宾格作逻辑主语）
    I will never forgive his betraying me by breaking his promise. （物主代词作逻辑主语）
    Mary excused the boy's upsetting the ink. （名词属格作逻辑主语）
前后呼应
    1. 主谓一致的基本原则：
     主谓一致有以下三条原则：
    1) 语法一致原则，即在语法形式上取得一致。例如，主语是单数形式，谓语动词也采取单数形式；主语是复数形式，谓语动词也采取复数形式。
    The students are very young.     This picture looks beautiful.
    2) 意义一致原则，即从意义着眼处理一致关系。例如，主语形式虽是单数但意义是复数，谓语动词也采取复数形式；而有些主语形式虽是复数但意义上看作单数，谓语动词也采取单数形式。
    The people in that country are fighting for independence.
    The crowd deeply respect their leader.
     Three years in a strange land seems a long time.
    3) 就近原则，即谓语动词的单数和复数形式取决于最靠近它的词语。例如：
    Neither he nor I am going to see the film tonight because we are busy.
    2. 主谓一致的用法
     根据以上三条原则，主谓一致有以下用法：
    1) 下列结构作主语，谓语动词一般用单数形式
    a. 表示时间、重量、长度、价值的名词作主语，谓语动词通常用单数形式。例如：
     Two hundred miles is a long distance.      Ten dollars is a high price for that book.
    b. 由 anyone, anything, anybody, no once, nothing, everyone, everybody , everything, someone, somebody, each, either, neither Someone is knocking at the door.
    Anything is better than going to the movie tonight.
    c. 由 “a series of, a kind of, a portion of+ 名词 ” 作主语，谓语动词应用单数形式。例如：
     A series of debates is scheduled to be held next week.
    d. 由 “many a, more than one+ 单数名词 ” 作主语，尽管意义上表示复数，但 谓语动词仍采用单数形式 。例如：    Many a person in these circumstances has hoped for a long break.
     There is more than one answer to your question.
    e.“ 名词 +and + 名词 ” 作主语，表示同一人、同一概念或事物时，谓语动词用单数形式。例如：
     A writer and educator is giving a lecture now. （这个人既是作家又是教育家）
    f.“either(neither)+of+ 复数名词（或代词） ” 作主语，谓语动词用单数形式。例如：
    If either of you takes a vacation now, we will not be able to finish the work.
    Neither of them wants to come.
    g. 在 each…and each…,every…and every… 等结构之后，谓语动词用单数形式。例如：
    Each man and each woman has the right to vote.
    h. 动词不定式、动名词或分句作主语时，谓语动词一般用单数形式。例如：
     What I want to say is none of your business.
    Listening to the classical music is enjoyable.
    i. 以 -ics 结尾的复数名词指一门学科时，如 politics （政治学）， mathematics （数学）， statistics （统计学）， acoustics （声学）， linguistics （语言学）等，谓语动词用单数形式。例如：
    Mathematics is what he majors in.
    2) 下列结构作主语，谓语动词单复数形式取决于 of 后的名词。
    a. 由 “all, none, no, most, half, the last, the rest, the remainder+of + 名词 ” 等不定代词作主语，谓语动词单复数形式 由 of 后名词的单复数而定 。例如：
    None of the food is wasted.     None of the students were absent.     The rest of the lecture was dull.
    The rest of the bikes were on sale yesterday.
    b. 由 “Lots of, heaps of, loads of , scads of + 名词 ” 作主语，谓语动词单复数形式由 of 后名词的单复数而定。例如：
    Lots of work is to be done this week.
    Lots of people are going to swim this afternoon.
    There is loads of milk on the farm.
    There are loads of big red apples on the ground.
    There is heaps of fun.
    c. 由 “ 分数或百分数 +of+ 名词或代词 ” 做主语，谓语动词的单复数形式取决于 of 后名词或代词的单复数形式。例如：     three-quarters of the area is cultivated.
    Ninety percent of the students have passed the exam.
    3) 下列结构作主语，谓语动词的单复数形式根据意义而定
    a. 由 “the+ 形容词 ” 这种结构作主语，根据意义一致的原则决定谓语动词的单复数形式。如果表示一类人（如 the rich, the poor, the blind, the deaf, the sick, the young, the old ），谓语动词用复数形式；如果表示个人或抽象概念，谓语动词用单数形式。例如：
    The blind are taught trades in special schools. （表示一类人）
    The good in him overweighs the bad. （表示抽象概念）
    The departed was a good friend of his. （表示个人）
    b.family,crowd,committee,class,audience,group,
government,team,public,majority,minotiry 等集合名词作主语，谓语动词单复数形式应根据意义而定。例如：
    The family like to listen to the music.(the family 指这家人，用作复数 )
    The family is small.(the family 指这个家庭，用作单数 )
    The committee has considered your proposal.(the committee 指委员会，用作单数 )
    The committee were arguing for an hour before they gave their votes.(the committee 指委员会的委员们，用作复数 )
    4) 下列结构作主语，谓语动词一般 单复数均可
    a. 以数词为名词词组中心词作主语时，谓语动词一般单复数均可。例如：
    Five and s, ix make/makes eleven.
    Seven times ten are/is seventy.
     但是： Twenty from thirty leaves ten.
    Six sevens are forty-two.
    b. 由 “one in/out of+ 名词 ” 作主语，谓语动词单数均可。例如：
    One in ten were/was present.
    5) 下列结构作主语，谓语动词用复数形式
     由 and 或 both...and 连接两个单数形式的名词词组作主语时，一般谓语动词用复数形式。例如：
    A girl and a boy want to go.
    Both rice and wheat are grown in that country.
    6 ）下列结构作主语，谓语动词单复数形式视具体情况而定
    a. 由 as well as, together with, besides, like, along with, without, except, accompanied by, rather than, including 连接两个名词作主语，谓语单复数形式应由连接词前的名词而定。例如：
    The president of the college, together with the deans, is planning a conference for the purpose of laying down certain regulations.
    The young mother with her two children is coming now.
    The plant manager, like many technicians, is experienced in designing new products.
    b.“ 名词 +of+ 名词 ” 作主语，谓语动词单复数形式跟 of 前的名词一致。例如：
    The picture of the children brings back many memories of my past experiences.
    The effects of cigarette smoking have been proved to extremely harmful.
    c. 由 not only...but also, either...or, neither...nor 或 or 连接的并列主语，通常根据 就近一致 原则，谓语动词的单复数形式由最接近它的名词词组的单复数形式决定。例如：
    He or you have taken my pen.
    Neither the students nor the teacher knows anything about it .
    One or two days are enough to visit the city.
    d. there- 存在句中的谓语动词单复数形式一般取决于其后的真正主语的复数形式。例如：
    There is a garden in front of the house.
    There are two things I'd like to say here.
7) 关于几对容易混淆词组的一致用法
    . 由 “this/that kind/type of + 名词 ” 作主语，谓语动词用单数形式；而由 “these/those kind/type of + 复数名词 ” 作主语，谓语动词用复数形式。例如：
     This kind of apples is highly priced.
     Those kind(s)of tests are good.
    b. 由 “a number of, a total of, an average of + 复数名词 ” 作主语，谓语动词用复数形式；由 “the number of, the total of, the average of + 复数名词 ” ，谓语动词用单数形式。例如：
     A number of students are waiting for the bus.
     The number of the students in this university is increasing yearly.
    c. one of, the (only)one of 的一致用法
    This is one of the books that have been recommended.
    This is the (only)one of the books that has been recommended.
    3. 前后呼应的用法
    1 ）当 everyone, everybody, none, nobody, anyone, anybody, someone, somebody,
    everything, anything, something, nothing 等用作主语时，其相应的代词一般用单数形式。例如：
    If anybody calls, tell him that I'm out.
    Something strange happened, didn't it?
    Every passenger has to carry his own luggage.
    2) 人称代词与名词的呼应：人称代词 I (me),he(him),she(her),it(it) 都是代替前面的单数名词，而 they(them),we(us) 则是代替复数名词的， you 既可以代表单数，也可以代表复数。但表示泛指的时候，用 he 或 one 来表示。例如：     If a young person enters a classical music field only for money, he is in the wrong profession.
    The leaves of the red maple are highly poisonous to horses and when ingested can kill them within fifteen hours.
    3) 物主代词与名词的呼应： my, our, his, her, its, their 要与代替的名词在数上一致。
     例如：     The welfare department, as well as the other social services, will have its budget cut.
    Dolphins are warm-blooded; that is ,their body temperature always stays about the same, regardless of the surroundings.
    4) 反身代词与其所代成分间的呼应
    Many primitive people believed that by eating an animal they could get some of the good qualities of that animal for themselves.
    Everybody clings to this illusion about himself.
    I have just been out to get myself a cup of tea.
    5) 指示代词与所代名词间的呼应： this 和 that 指单数名词或不可数名词， these 和 those 指代复数名词（ those 还可以用作先行词，引导定语从句，表示 “ 那些人 ” ）。例如：
    She invited all those who had been her former colleagues:
    The amount of the pressure caused by the weight of a column of fluid is determined by the height of this column.
    6 ） much 和 much of 后接不可数名词，而 many 和 many of 后接可数名词的复数。
例如： There is not much coal left.
    A great many of the houses were knocked down by the earthquake.
    7) 表示量的词后面有的接可数名词，有的接不可数名词的复数。接可数名词的有： a number of ,a range of, a series of + 复数名词；接不可数名词的有： a great deal of ,an amount of + 单数不可数名词；既可接可数又可接不可数名词的有： a lot of , a variety of 。例如：
    The government attached a great deal of importance to education.
    Quite a number of women applied for this job.
    The college library has a variety of books.
    An apple is a variety of fruit.
    A wide range of disorders can affect the human muscular system.
反意疑问句     反意疑问句主要由 “ 陈述句 + 反意疑问 ” 构成，反意疑问部分的动词一般要与陈述部分的动词相对应，反意疑问部分的主语要与陈述部分的主语相对应，如果陈述部分的主语是名词，则反意疑问部分用相应的代词表示。
    1. 反意疑问句的形式
     反意疑问句一般有以下四种形式：
     肯定陈述句 + 否定反意疑问句。例如：
    This pencil is red, isn't it?
     否定陈述句 + 肯定反意疑问句。例如：
    This pencil isn't red, is it?
     肯定陈述句 + 肯定反意疑问句。例如：
    This pencil is red, is it?
     否定陈述句 + 否定反意疑问句。例如：
    This pencil isn't red, isn't it?
     前两种形式是主要的，后两种不常见。
    2. 反意疑问句的用法
    1 ）当陈述部分是 there 存在句时，反意疑问部分的主语用 there 。例如：
    There aren't a lot of flowers in the garden in winter, are there?
    There existed different opinions on this issue, didn't there?
    2 ）当陈述部分是以不定代词 one 作主语时，反意疑问句的主语在正式场合用 one, 在非正式场合用 you 。例如：
    One cannot succeed at this, can one?
    One cannot succeed at this, can you?
    3 ）当陈述部分是 I'm... 结构时，反意疑问部分一般用 aren't I 。例如：
    I am a student, aren't I?
    4 ）当陈述部分是一个带有 that 引导的宾语从句的复合结构时，反意疑问部分一般根据主句的主语和谓语动词而定，例如：
    You told me (that)I had passed the exam, didn't you?
    He says that everybody in our class will attend the meeting, dosen't he?
     但是，当陈述部分的主句是 I think, I suppose, I believe 等结构时，反意疑问部分则往往由 that 从句中的主语和谓语动词决定，并且要注意否定的转移。例如：
    I believe(that)it is going to rain, isn't it?
    I don't think (that)he will come, will he?
    5 ）当陈述部分的谓语动词是 have 时，反意疑问部分要根据 have 的意义及形式而定。
    a. 当 have 表示 “ 所有 ” 含义时，反意疑问句以用 have 形式，也可以用 do 形式。例如：
    He has a book in his hand, hasn't he?
    He has a book in his hand, doesn't he?
    b. 当陈述部分的动词是 have 的否定形式时，反意疑问部分是用 have 形式还是用 do 形式，取决于陈述部分的动词形式。例如：
    You haven't a car, have you?
    You don't have any money with you, do you?
    c. 当 have 不表示 “ 所有 ” 含义而表示其他含义时，反意疑问句则必须用 do 的形式。例如：
    We had a good time in the vacation, didn't we?
    He has his breakfast at seven everyday, doesn't he?
    You have to get up early tomorrow, don't you?
    6 ）当陈述部分带有 never, nothing, nowhere, seldom, hardly,rarely, few, little
     等否定词或半否定词时，反意疑问部分的动词用肯定形式。例如：
    The summit meeting never took place, did it?
    You can hardly believe what he said, can you?
    There is little ink in the bottle, is there?
     Few people know this place, do they?
     当陈述部分的谓语动词是带有 un- ， in- ， dis- 等否定前缀的动词，则仍然把陈述部分看作肯定句，那么反意疑问部分用否定形式。例如：
    He is impolite to the teacher, isn't he?
    He distrusted anybody around him, didn't he?
    7 ）当陈述部分带有情态动词 ought to 时，反意疑问部分在英式英语中用 ought to 形式，在美式英语中用 should 形式。例如：
    You ought to see the new picture, shouldn't you?
    Teachers ought to be honored, oughtn't they?
    8 ）当陈述部分带有情态动词 used to 时，反意疑问部分可以用 used to 形式，也可以用 did 形式。例如：
    She used to live abroad, usedn't she?
    There used to be a newsstand in the corner of the street, didn't there?
    9 ）当陈述部分带有情态动词 must 时，反意疑问部分需视 must 的含义而定。
    a. 当 must 表示 “ 命令或强制 ” 时，反意疑问部分用 mustn't 。例如：
    You must do it by yourself, mustn't you?
    b. 当 must 表示 “ 有必要 ” 时，反意疑问句用 needn't ，例如：
    You must see him tonight, needn't you?
    c. 当 must 表示 “ 一定 ” 或 “ 想必 ” 等推测意义时，反意疑问部分不用 mustn't ，而根据 must 后的动词形式而定。例如：
    He must be crazy to do so, isn't he?
    She must have been there for a long time, hasn't she?
    They must have stayed at home last might, didn't they?
    10 ）当陈述部分带有 need 时，反意疑问部分需视 need 的含义而定。如果 need 用作情态动词，则反意疑问部分用 need 形式；如果 need 用作实义动词，表示 “ 需要 ” ，则反意疑问部分用 do 形式。例如：
    You needn't go there, need you?
    She needs to fo there, doesn't she?
    Plants need sun to grow, don't they?
    11 ）当陈述部分带有 I'd better 或 I'd rather 时，反意疑问部分用 hadn't 或 wouldn't 。例如：
    You'd better finish the task before tomorrow, hadn't you?
    He'd rather stay with us, wouldn't he?
    12 ）当陈述部分是祈使句时，反意疑问部分一般用 will you ， won't you, would you 。例如：
    Don't be too late, will you?
    Close the door, won't you?
    Come here, will you?
    Open your books, would you?
     当陈述部分是以 Let's 开头的祈使句时，反意疑问部分用 shall we ；若是以 Let us 开头的祈使句，反意疑问部分则用 will you 。例如：
    Let's have a party tonight, shall we?
    Let us have a look at you pictures, will you?
     注意，如果祈使句是否定形式，那么反意疑问句只能用 will you 。例如：
    Don't forget to bring your notebooks here tomorrow, will you?
分词
    1. 分词的形式
     这里所讲的分词包括 -ing 分词和 -ed 分词，即传统意义上的现在分词和过去分词。现在分词由动词原形 +-ing 构成（如 listening ）；过去分词通常由动词原形 +-ed 构成（如 listened ），也有不规则形式（如 go-gone ）。现代英语的绝大多数都是规则动词，不规则的只是少数。
    2. 分词的基本用法
     分词在句中通常可以用作表语、定语、补语和状语。下面按照现在的分词和过去分词的用法分别作介绍。
     现在分词的基本用法：
     现在分词表示主动的意义；表示一般性的或正在进行的动作；在表面形式上有 “ 一般式 ” 和 “ 完成式 ” 与 “ 主动式 ” 和 “ 被动式 ” 之分。
    1 ）作表语
     现在分词作表语通常表示主语所具有的特征。例如：
    This story quite interesting.
    The journey without you will be boring.
    2 ）作定语
     现在分词可以单独作定语，也可以构成合成词作定语，但在更多的情况下是分词短语作定语，包括限定性和非限定性（用逗号与其他部分分开），在意义上相当于一个定语从句。现在分词作定语通常带有主动意义和未完成意义。例如：
    The man following was obviously in a hurry 。（现在分词单独作定语）
    They acted just like a conquering army 。（现在分词单独作定语）
    Do you know the man standing over there by the motor car? （分词短语作限定性定语。）
    Last night, we caught a thief stealing John's bike. （分词短语作限定性定语）
    3 ）作宾语补足语
    a. 表示感觉和心理状态的动词，如 hear, feel, find, listen to, look at, watch,
    notice, observe, smell see 等词的宾语可以用现在分词作宾语补足语。例如：
    I noticed him slipping away before the end of the meeting.
    I can smell turkey roasting, and it's making me hungry.
    b. 表示 “ 致使 ” 等意义的动词，如 catch, get, have, leave, set 等词的宾语可以用现在分词作宾语补足语。例如：
    Please don't keep the machine running while you are away.
    4 ）作状语
     现在分词作状语表示主语在进行一动作的同时所进行的另一动作，它对谓语动词起修饰或陪衬的作用。这时要注意现在分词与其逻辑主语在时态和意义上的统一。例如：
    Rushing out of the room, he has knocked down by a car. （作时间状语）
    =When he rushed out of the room, he was knocked down by a car.
    Working harder, you will pass the entrance exam. （作条件状语）
    =If you work harder, you will pass the entrance exam.
    She sat at a window and read a book. （作伴随状语）
    =She sat at a window and read a book.
    Having won the championship, he was awarded a million dollars. （作原因状语）
    =Because he had won the championship, he was awarded a million dollars.
    Even if taking a taxi, I will still be late for the meeting. （作让步状语）
    =Even if I take a taxi, I will still be late for the meeting.
    The road is under construction, thus causing the delay. （作结果状语）
    =The road is under construction, and thus caused the delay.
     注意，当现在分词作让步状语时，一般放在句首，常常由 although, though, even if , unless 等连词引入；作结果状语时，一般放在句末，前面可 so, thus, hence ， thereby 等副词。
     过去分词的基本用法：
     与现在分词不同，过去分词表示被动的意义，表示已经完成和被动的动作。在表现形式上，只有一种形式。
    1 ）作表语
     过去分词作表语表示主语所处的状态。用作表语的过去分词大多来自及物动词；不及物动词的过去分词能作表语的只限于少数表示位置转移的动词，如 go, come, assemble 等，它们用在联系动词之后，表示完成意义，无被动意义。例如：
    The man looked quite disappointed.
    He is greatly discouraged by her refusal.
    His hair is nearly all gone.
     已经形容化了的过去分词大多可作表语，常见的有 accomplished, amazed, amused, astonished, broken, closed, completed, complicated, confused, crowded, devoted, disappointed, discouraged, drunk, excited, frightened, hurt, interested, lost, satisfied, surprised, worried 等。
    2 ）作定语
    a ）用作前置定语的过去分词通常来自及物动词，带有被动意义和完成意义。例如：
    We like skating in the frozen lake in the winter.
    =We like skating in the lake which has been frozen in the winter.
    How many finished products have you got up to now?
    =How many products that have been finished have you got up to now?
     来自不及物动词的过去分词很少能单独用作前置定语，能作这样用的仅限以下几个词，这时仅表示完成意义，不表示被动意义：
    a retired worker=a worker who has retired
    an escaped prisoner=a prisoner who has escaped
    a faded/withered flower=a flower that has faded/withered
    fallen leaves=leaves that have fallen
    the risen sun=the sun that has just risen
    a returned student=a student who has returned
    vanished treasure=treasure that has vanished
    b) 用作后置定语的过去分词通常也来自及物动词，表示被动意义和完成意义。这相当于一个定语从句。例如：
     Things seen are better than things heard.
    =Things which are seen are better than things which are heard.
    The lobster broiled over charcoal was delicious.
    =The lobster which was broiled over charcoal was delicious.
    3 ）作宾语补足语
    a ） see hear, feel, find, think 等表示感觉和心理状态的动词可以带过去分词作宾
     语补足语。例如：
    Tom found himself involved in an awkward situation.
    I saw Tom dressed like a beggar in the street.
    Everybody thought the match lost until the last minute.
    b ） make, get, have, keep 等表示 “ 致使 ” 意义的动词可以带过去分词作宾语补足语。
     例如：
    I have my clothes washed everyday.
    Don't get your schedule changed; stay with us in the class.
    He's trying to make himself understood.
    Please keep us informed of the latest price.
    c)like, want, wish, order 等表示希望、要求、命令等意义的动词可以带过去分词作宾语补足语。例如：
    We don't like such topic(to be)discussed in class.
    I wish this problem(to be)solved this week.
    4) 作状语
     用作状语的过去分词通常来自及物动词。过去分词用作状语时，修饰主句的谓语动词，意义上相当于状语从句，表示时间、条件、原因、伴随状况等。过去分词作状语，前边往往可以加 when, while, if, as if, though 。一般说来，这种结构的逻辑主语必须与主句的主语一致。例如：
    Whenever praised, she blushes. （作时间状语）
    =Whenever she is praised, she blushes.
    United, we stand; divided, we fall. （作条件状语）
    =If we are united, we stand; if we are divided, we fall.
    Written in great haste, this book is full of errors. （作原因状语）
    =Because this book in written in great haste, it is full of errors.
    Mary was reading a love story, and was completely lost to the romantic life. （作让步状语）
    =Mary was reading a love story, and was completely lost to the romantic life.
    Although born in Germany, John lives and works in U.S.A 。（作让步状语）
    =Although John was born in Germany, he lives and works in U.S.A 。

    3. 分词的完成式及被动式
     前面提到过，过去分词只有一种形式，所以这里所讲的完成式及被动式均指现在分词的完成式及被动式。
     如果现在分词表示的是一般性动作，不表明动作的先后或与谓语动作同时发生，这时要用现在分词的一般形式。例如：
    Living in the downtown, we found a lot of amusements.
     如果现在分词所表示的动作先于句子谓语发生，就要用现在分词的完成式 “(not)having+ 过去分词 ” 。例如：
    Having heard from my father, I was relieved.
    Not having received any letter from my family, I was worried.
     如果现在分词的逻辑主语是现在分词所表示的动作的对象，则要用现在分词的被动形式，包括其一般形式 “（ not ） being+ 过去分词 ” 和其完成形式 “ （ not ） having been+ 过去分词 ” 。例如：
    Upon being questioned, he denied having robbed the bank.
    The new method, having been widely used abroad, can increase the working efficiency.
    4. 分词独立结构
     如果过去分词或现在分词带有与句子主语不同的主语，这就构成了独立结构，也叫独立主格结构或垂悬结构，通常在句中起状语从句的作用，表示原因、时间、条件、方式或伴随状况。
     例如：
    The holidays being over, they began to get down to do their work again.
     （原因状语）     =As the holiday was over, they began to get down to do their work again.
    All things considered, her paper is of greater value than yours. （条件状语）
    =If all things are considered, her paper is of greater value than yours.
    His homework done, Johan went out to play. （时间状语）
    =After his homework had been done, Johan went out to play.
    The girl was smiling sweetly, her long hair flowing in the breeze. （伴随状语）
     当独立结构表示伴随状况时，可变为由 with 引导的介词词组，而表示否定意义的类似结构便可由 without 引导。例如上例可变为：
    The girl was smiling sweetly with her long hair flowing in the breeze.
    Without anyone noticing, I slipped out of the room.
     独立结构的位置比较灵活，它可以置于句首、句中或句末。另外，独立结构中用作主语的名词之前的限定词有时可以省略。例如：
    The manager sat quietly in his office, (his)eyes closed.
    He stood in the doorway, (his)wet cloak dripping water on the rug, and waited for some sign of recognition. 倒装句
    倒装句主要出现在以下几种情况下：
    1. 当表语前置时，如果主语较长或主语结构比较复杂，需要倒装。例如：
    Happy indeed are those who receive marvellous news after a long silence.
    Absurd was the measure our company took to prevent loss.
  2. 当前置宾语或状语由 “not a /many a /not a single+ 名词 ” 构成时，需要倒装。例如：
     Not a word did he say at the meeting yesterday.
     Many a time has the teacher emphasized the point.
     Not a single hotel could she find in the small town.
    3. 最通常引起倒装的是某些状语的前置。通常有以下几种情况：
    1 ）当句首状语为否定词或有否定意义的词语时，一般需要倒装。常见的否定副词有：
    not, little, never, nowhere, hardly, scarcely, rarely, seldom, not only(...but also/as well...),not until, not once, no sooner. 例如：
    Never have I heard it before.
    Not only did Mary passed the exam, she also got the highest mark in her class.
    Nowhere can I find my lost wallet.
    Seldom do I get invited into his office alone.
    All pupils live nearby, Rarely do they go to school by bus.
    2 ）当句首状语为否定意义的短语时，需要倒装。常见的否定短语有： at no time
    ,in no way, on no account, at no point, in no sense, by no means, under no circumstance. 这些短语都表示 “ 决不 ” 。例如：
    Under no circumstance do we use the weapon.
    At no time shall a student cheat in the exam.
    On no account should you leave tonight.
    By no means is he considered to be a great explorer.
    In no sense is her mind brilliant.
    In no way can a passenger smoke in the air-conditioned bus.
    3 ） hardly/scarcely...when, no sooner...than 位于句首时，为固定的倒装结构表示 “ 一 …… 就 ……” 。在时态上，主句一般用过去完成时，从句（ when 或 than 引导）用一般过去时。但表示一般情况时，主句可用现在完成时，从句用一般现在时。例如：
    Hardly had he begun to speak when the audience interrupted him.
    No sooner had I left the house than it began to rain.
    Scarcely had she put down the receiver when the telephone rang again.
     但如果用于句中，则不必倒装。例如：
    I had no sooner left the house than it began to rain.
    4 ）当句首状语为表示地点的介词词组时，也常常需要倒装。倒如：
    At the side of the hill stood an old house.
    In this chapter will you find the answer to my question.
    5 ）当句首状语由 only+ 副词， only+ 介词词组， only+ 状语分句构成，也可以倒装。例如：
    Only yesterday did the new students come.
    Only with the help of his friends can Jim find a job.
    Only after they performed the experiment did they succeed in solving the problem.
    6 ）以关联词 so(...that) 开头的句子，通常引起倒装。在这种结构中， “so+ 形容词 ” 是表语的前置； “so+ 副词 ” 是状语的前置。例如：
    So cold was it at night that I could hardly fall asleep.
    So quickly did the workmen finish the work that they were given a bonus.
    4. 如果第一分句是肯定句，第二分句用 so+ 倒装结构；如果第一分句是否定句，第二分句用 neither/nor/no more+ 倒装结构。例如：
    I could not afford to eat in the restaurants, and nor could anyone I know.
    I have made the decision, and so has he.
    You haven't finished reading the book, no more have I.
     但是，如果第一句是肯定句，第二句用 so+ 主语 + 情态动词，则表示 “ 的确是这样 ” 。例如：
    It is said that Tom is clever, and so he is.
    5. 虚拟结构中倒装
     在虚拟结构的条件从句中，如果 if 被省略，那么 were, had 或 should 要移至主语之前，形成倒装结构。例如：
    Were he to start today, he would arrive there on Thursday.
    =If he were to start today, he would arrive there on Thursday.
    Had it not been for his kelp, we couldn't have overcome the difficulties.
    =If it had not been for his help, we couldn't have overcome the difficulties.
    Should it rain tomorrow, I would stay at home.
    =If it should rain tomorrow,I would stay at home.

6. 为了强调从句中的某个成分（通常为补语或状语）的倒装：将被强调成分放在句首，从句由连词 as, though 引导，但这时不用全倒装。例如：
    Old as he is, he still studies hard.
    =Though he is old, he still studies hard.
    Difficult as the task was, they managed to accomplish it in time.
    =Though the task was difficult, they managed to accomplish it in time.
     注意：
    1 ）否定副词如果只是限定句子主语而非修饰谓语或全句，则句子不必倒装。例如：
    Hardly anyone has ever been invited.
    2 ）某些否定词，如 no 或 not ，修饰主语而不是作状语时，句子也不必倒装。例如：
    No survivor has ever been found.     Not all that glitters is gold.
    Not all valleys are on dry land.