PETS公共英语四级语法.docx

1、PETS公共英语四级语法PETS第四级重点语法资料1、 It做形式主语1） It可以用作先行词，作为句子形式上的主语，而把真正的主语移到句子后部去。这种it成为先行主语（Preparatory Subject）。这样可以使句子变得更平稳，避免主语太长，显得头重脚轻。可移到句子后部去的主语最常见的是不定式。句子谓语主要有下面几种类型：a、be+形容词+不定式：It is easy to criticize others.批评别人是容易的。（比较：To criticize others is easy）Its nice not to be dependent on them.不依靠他们是好的。b、

2、 be+名词+不定式：It was his duty to take care of the orphans.照顾孤儿是他的职责。Its a privilege to visit your country.访问贵国是一大荣幸。c、 be+介词短语+不定式：It was against my principle to do that.做这样的事有悖我的原则。Its beyond me to say why.我无法说明原因。d、 及物动词+宾语+不定式：It cost 100 dollars to repair the car.修车花了一百美元。It takes two to make a qua

3、rrel.一个巴掌拍不响。It makes me sick to think about that.想起那事就让我恶心。不定式前有时可有for引导的短语，表示其逻辑上的主语：What time would it be most convenient for me to call again?什么时候我再来方便？Its getting harder every day for a poor man to get a living.穷人维持生计日益困难。2） 用it作先行主语，代表动名词的情况也不少，这类句子用“be+名词”作谓语时最多，也可以“be+形容词”或其他结构作谓语。a、Its no u

4、se studying for an exam at the last minute.临时抱佛脚来应考是没用的。 Its no good standing here in the cold. Lets go home.在这寒风中站着没好处，咱们回去吧。b、It is worthwhile quarrelling with him?和他吵值得吗？ Its hopeless trying to convince her.想说服她是没有希望的。c、It doesnt matter waiting a few days.再等几天没有关系。 It doesnt make any difference m

5、y being there.是否在那里无所谓。3）用it可以引导强调句： It was Peter who lent us the money.是Peter借了钱给我们。 Its today that hes going.它是今天走。（不是明天）4）如果将it+be置于find/think(that)之后，通常be和that可省略：He thought (that) it (would be) better to say nothing.他认为不说话为妙。2、形容词比较级的特殊用法形容词比较急有些特殊用法，例如：1）morethan有时可以把两种品质加以比较，表示“更多而不是”：This is

6、 more a war movie than a western.这应当说是一部战争片而不是西部片。2）more and more 这里结构可表示“越来越”：The story gets more and more exciting.故事变得越来越激动人心。3）the morethe more可表示“越是越”The warmer the weather, be better I feel.天气越暖和我感觉越舒服。4）more than常用在数词前，表示“超过”“多”：He cant be more than thirty.他不可能超过三十岁。More than 800 people atten

7、ded the concert.八百多人出席了音乐会。5）less than常表示“不到”或（美）“不太”：In less than a week, the MS was ready.不到一周稿子就准备好了。I bought it for less than a dollar.我买它花了还不到一美元。6）no less than表示“多达”、“不少于”：He won no less than 500 pounds.他赢了不少于五百英镑。Its population is no less than two million.它的人口多达两百万。7）more or less表示“基本上”、“大体上”

8、或“大约”：The work is more or less finished.这项工作基本上完成了。3、现在分词和过去分词英语中的分词有两种：现在分词和过去分词。现在分词由动词原形加-ing构成，过去分词由动词原形加-ed构成，现在分词表示正在进行或主动意义，过去分词表示已经完成或被动意义，两者之间既有相同之处，又有区别。1）现在分词表示正在进行的动作，而过去分词则表示完成的动作，如： falling leaves正在飘落的树叶 fallen leaves 落叶（已落下的树叶） boiling water 沸水（正在沸腾的水） boiled water 开水（以烧开的水，可能已凉了） dev

9、eloping country 发展中国家（正在发展的） developed country 发达国家（发展完了的）2）现在分词表示主动的意义，所修饰的人或物是分词动作的执行者，过去分词表示被动的意思，所修饰的人或物是分词动作的承受者，如：an exciting film 一个激动人心的电影 excited audiences 激动的观众I heard someone closing the door.我听见有人在关门。I heard the door closed.我听见门被关了。3）分词的否定式（由“not+分词”构成）Not daring to speak, they sat there

10、 silent.他们不敢说话，坐在那里一声不吭。Not having found the wallet, he dared not go home.他没有找到钱包，不敢回家去。He escaped, not seen by anyone.他逃走了，没有人看见。4、情态动词+have done情态动词+动词完成式即“情态动词+have done”，表示对过去行为或动作表示推测、评论或判断。这个结构是近几年PETS考试中情态动词的重点和难点。一、在虚拟语气中的用法1、should have done表示“过去本应该做某事却未做”。其否定结构shouldt have done表示“过去本不该做某事却

11、做了”。2、ought to have done表示表示“过去本应该做某事却未做”。其否定结构oughtnt to have done表示“过去本不该做某事却做了”。3、need have done表示“过去本有必要做某事却未做”。其否定结构neednt have done表示“过去本没必要做某事却做了”。4、could（不能用can） have done表示“过去本能够做某事却未做”。注意：其否定形式couldnt have done没有虚拟语气的用法。couldnt have done只能表推测，相当于cant have done，意为：“过去不可能做了某事”。5、might（不能用may

12、） have done表示“过去本可以做某事却未做”。注意：其否定形式might not have done没有虚拟语气的用法，might not have done只能表推测，相当于may not have done，意为：“过去可能没有做某事”。二、表推测的用法1、must have done表示对过去某事的肯定猜测，译为：过去肯定做了某事。不存在mustnt have done的形式。其否定或疑问形式须用can(could)来表示。例如：Since the road is wet, it must have rained last night.既然路是湿的，那昨天晚上肯定下雨了。He c

13、ant have missed the way. I drew him a map.他不可能迷路。我（当时）给他画了张图。2、may/might have doneMay/might have done表示“过去可能做了某事”。may比might 表示的可能性在说话人看来稍大些。may/might not have done表示“过去可能没有做某事”。例如：I cant find my keys. I may/might have left them at the school yesterday.我找不到我的钥匙了。我可能昨天把他们落在学校了。John may/might not have

14、passed the exam, he looks very sad.John可能没有通过考试。他看起来很忧伤。注意：may/might have done表推测不能用于疑问句中。3、can/could have done表推测，一般用在否定句和疑问句中，表示不相信或怀疑的态度。Can/Could he have passed the exam?他可能通过考试了吗？I think that he couldnt/cant have gone abroad. I saw him just now.我认为他不可能出国了。我刚才还看见他了。注：表示推测过去某动作发生的可能性是，就表示的可能性程度而言

15、，must最大，could其次，may更次之，might最小。例如：I wonder how Tom knew about your past.我想知道Tom是怎么知道你的过去的。He must/could/may/might have heard of it from Mary.他肯定/很可能/可能/也许已从Mary那儿听说此事了。5、动词不定式1、不定式做主语一般表示具体的某次动作。To complete the 30-storied building in one year was quite a difficult task.To do that implies taking resp

16、onsibility.当主语较长，谓语较短时，常用it做形式主语，而将不定式放到谓语的后面。如：It is important for modern young people to master at least two foreign languages.It做形式主语，不定式放在谓语动词之后常用于下列结构中：A. It is+形容词+(for/of sb.)+不定式，如：It is not easy to catch fish with your hands only.It is important for us young people to learn English and mast

17、er it.B. It is+名词+不定式It is a pity to have to go without her.C. It takes (sb.) some time +不定式It takes me three hours to learn English each day.2、不定式作表语不定式作表语常表示将来的动作，主语常常是表示意向、打算、计划的词(idea, task, purpose)等,如：The most important thing for ones health is to have plenty of exercise.3、不定式作宾语I like to go o

18、ut for walks in the warm sunshine in spring.She failed to finish the assignment in time, and she was worried about it.4、“wh-+不定式”结构不定式前加一个疑问代词（what, which, who, whom, whose）或疑问副词（where, when, how, why），以及连词whether构成特殊的不定式短语，其作用相当于一个从句，这样的不定式短语常常在某些动词后面作宾语。I couldnt decide which book to choose.I can

19、tell you where to get this book.“wh-word+不定式”结构除了作宾语外，还可以在句中作主语或者表语。如：When to start the program remains undecided.The question is how to put the plan into practice.5、不定式作状语A.不定式作状语表示目的。或用于so as和in order之后，来强调这种目的。如：To learn a foreign language well, you must make painstaking efforts.B.不定式表示结果，特别是在soa

20、s to, suchas to, only to以及tooto等结构中的不定式表示结果。如：She left her hometown with her beloved man, never to return.No one is too old to learn.Would you be so kind as to carry the luggage for me?C.不定式常用来修饰形容词，构成词组，如：It is likely to rain today, for it is very cloudy.I am willing to help you with your homework,

21、 for we are friends.6、不定式作宾语补语不定式长跟在动词之后作宾语补语，如：He asked you to call him at ten oclock.Id never allow my children to behave like that.当不定式在let, make, have, 感官动词后面作宾语补语时，不定式不带to。如：Whenever something is wrong with you, please do let me know.I will have the students write a passage about Internet.7、不定式

22、作定语A.不定式作定语通常要放在其所修饰的名词或代词之后。不定式常作名词定语，如：His efforts to carry out the plan were successful.There is no need to bother him with such trifles.B.由only, last, next, 序数词或形容词最高级修饰的名词常用不定式作定语。如：Mr Zhang is always the first man to arrive at the office and the last man to leave.I dont think he is the best on

23、e to do the work.8）不带to的不定式在下列词组后面的不定式不带to：would ratherthan（宁愿也不），had better（最好），cant help but（不得不），had rather（宁愿），cannot but（不得不，必然），may/might as well（不妨），let alone（更不用说）。如：I cant help but wish that nothing would go wrong.They had never seen such delicious food, let alone eat it.9）不定式的完成式to have do

24、ne表示在谓语动词之前已经发生的动作，而不定式的一般式to do表示动作将要发生。不定式还有其被动形式：to be done（表示将来的被动动作）和to have been done（表示过去的被动动作）。6、动名词1、在某些动词后面只能用动名词，如：He hasnt finished reading the novel. 他还没有看完那部小说。We must practice speaking English. 我们必须练习讲英语。2、 某些动词后接动名词与接不定式意义不同。如：He stopped singing.他停止唱歌。 She tried pushing the door.她试着推

25、门。He stopped to sing.他停下来去唱歌。 She tried to push the door.她试图把门推开。She remembered posting (having posted) the letter at the post-office.她记得在邮局寄了那封信。She remembered to post the letter at the post-office.她记得要在邮局寄那封信。3、 下列短语中的to是介词，其后跟动名词，不跟不定式。be(get) used to 习惯于；look forward to 盼望；pay attention to 注意；ge

26、t down to 开始认真做；lead to 通向、导致；prefer doingto doing 宁愿做而不愿做；stick to 坚持；devote ones life(time, oneself) to 献身于、致力于；object to 反对；in addition to 除之外；on the way to 在去的路上、正要成为4、 在动词need, want, require后面，用动名词的主动形式表示被动的意义。用不定式时要用它的被动形式，如：The house needs repairing. 房子需要修理5、 be worth后面的动名词用主动形式表示被动含义，如：The b

27、ook is worth reading. 这本书值得读一读。6、 一些动词短语如feel like, cant help等后需要接动名词，如：I dont feel like going to see a film. 我不想去看电影。The child couldnt help laughing when he saw the monkey.这孩子看到猴子不禁笑了起来。7、 动名词除了其一般式doing，还有完成时having done以及一般式的被动形式being done和完成式的被动形式having been done；动名词前可以加上逻辑主语，构成动名词的复合结构：ones doin

28、g。例如：Im sorry for not having kept my promise. 非常抱歉，我没能遵守诺言。（not having kept my promise发生在am sorry之前）Do you mind Mary being left alone at home? 你介意Mary被单独一个人留在家里吗？7、主谓一致1、主语是抽象概念短语或从句作主语时，谓语用单数形式。 Collecting stamps is my favorite hobby.（动名词短语作主语） That we have made such progress is a fact.（从句作主语）2、wha

29、t或which引导的主语从句的句子，谓语动词或系动词与表语的数一致。 What I want is a new bicycle. Which are your pictures?3、两个以上的主语用and或both连接时，谓语用复数形式。例如： Both Tom and Dick are good friends.4、and所连接的两个词如指同一主体时，谓语则用单数形式。例如： A singer and dancer was present at the party today. A singer and a dancer were present at the party today.5、集

30、体名词作为整体意义时，谓语用单数形式，若指成员意义时，谓语则用复数形式。例如： My family is a big one. My family are watching TV now.6、主语是单数后面跟有as well as, with, together, like, but, except等短语时，谓语动词仍用单数形式。 （1）Kelly as well as the other students has learned how to type. （2）Our school, with some few schools, was built in the 1960s.7、两个主语由n

31、ot onlybut also, eitheror, neithernor相连接时，在肯定句中谓语变化取决于后者，在疑问句中取决于前者，例如： Not only my parents but also my teacher has been to the party. Either he or I am to go there. Neither the students nor the teacher likes the film.8、 people, police, cattle（牛群）, militia（民兵）作主语时，谓语用复数形式。例如：The police are still running after the murderer.The cattle are grazing(放牧) in the fields.9、 half of+单数名词时，谓语用单数形式；half of+复数名词时，谓语用复数形式。例如：Half of the apple is rotten. Half of the apples are rotten.10、书名、国名等名词作主语时，谓语用单数 Hamlet was written by Shakespear.