中考复习专题情态动词

1、. 专题八 情态动词 情态动词本身有一定意义，表许诺、愿望、义务、命令和猜测。它必须和动词原形一起构成谓语。情态动词没有人称和数的变化。把情态动词放在句首、句尾用问号便构成疑问句；在其后加上not或never等否认词就构成否认句。一、常见情态动词的用法一can/ could的用法1.表示具备某种“才能，但不一定做事情，仅仅表示有才能而已。could是can的过去时：Can you swim across the river?你能游过那条河吗？2.表示“恳求疑问句中、“允许。Could比Can委婉；两者都指如今。答复一律用can, may或of course,否认用mustnt。3.表示“可能性

2、，都可以表示如今和将来，只是could的语气更加不肯定。否认式表示“不可能，如：They cant/ couldnt be doing that now.二may/ might的用法1.表示允许或恳求允许，might语气更委婉。肯定答复用may/ might/ can，否认答复用may not, cant, mustnt.May I turn on the TV?Yes, you may/ can.No, you cant/ mustnt.2.表示可能性，“也许。这时may和might表如今，只是might在语气上更不肯定一些。如：You may/ might have some fever.

3、表示可能性时，may/ might不用于疑问句，可用can/could或别的说法。如：Is it likely to rain?3.祈使句中表示祝愿：May you succeed!三must的用法1.表示义务、命令或劝告，“必须。You must tell me the truth.你必须和我说实话。在答复由must引起的问题时，否认答复用neednt或dont have to,表示“不必、没必要；而mustnt表示“不准许的意思。Must the ladies wear dresses?No, they dont have to / they neednt.2.表示推测，“肯定。此时，mu

4、st只用于肯定句。在否认句或疑问句中，用can/ could：There must be a mistake. Can / Could there be a mistake?四need和dare的用法情态动词need“需要和dare“敢通常只用于否认句和疑问句中。You need not come so early. How dare you be so rude?但need和dare可作为实义动词，后跟动词不定式，可用在所有句型中，注意此时他们的否认式和疑问式与情态动词不同。五shall和will的用法1.shall用在第一、三人称作主语的疑问句中，来征求意见。Shall I go now?

5、 Shall we invite her, too?2.shall用于所有人称，表示说话人的决心、保证、许诺、威胁、警告、命令等强烈的感情，如：You shall have an answer by tomorrow. He shall suffer for this.3.will可以表示“愿意、肯、会、固执等意义，而非将来，would那么更婉转：I will pay for it. Were going on a climbing trip. Come if you would.4.will可以表示倾向、习惯，在否认句中可以表示“不肯、不能等意思：Oil and water will not

6、 mix. This machine wont work.5.would可以表示过去的习惯，类似used to：He would come to see me on Sunday when he was here.六should / ought to的用法 两者大多数情况下可以互换。Ought to的否认式为ought not to / oughtnt to 。1.表示道义上的责任，义务或要求，有时表示劝告，“应该，如：You ought to / should pay more attention to what your teacher says.2.表示对如今和将来的推测：This pe

7、n ought to/ should be yours.3.“should/ ought to have+过去分词表示对过去的推测，“应该已经。有时表示“本应该做而没有做；“should not/ ought not to have+过去分词表示“做了不应该做的事情，是“本不该的意思，因此它们都含有责备的语气：He began two hours ago. He ought to have finished filling in the forms now. You should not have asked him for help.4.表示讲话人惊奇，绝望，愤怒等感情：Why should

8、 I believe you? Whats happened to that money? How should I know?七had better表示“最好，后接动词原形，其否认式为had better not+ 动词原形would rather意思是“宁愿，表示选择。它有两种用法：一是在肯定句中后边直接跟动词原形，其否认句是在would rather后加not，即：would rather not+动词原形；二是它后边可以接从句，该从句的谓语动词用一般过去式表示虚拟语气。由于would rather表示选择，它后边可接than。二、情态动词+ have+ done一must have d

9、one表示对过去的推测，意思是“一定已经，想必已经，准是已经，只用于肯定句中。The streets are wet. It must have rained.街道是湿的，准是下雨了。否认要用“cant/ couldnt+ have+过去分词，意思是“不可能：The pocket cant have been lost there.二may/ might have done表示对过去的推测，意思是“也许已经 ，可能已经。用于肯定或否认句中。疑问句中用can或could.此外，“might have+过去分词也表示“本来可以但没有实现的意思，含有责备的口气。例如：He may have gone

10、 to bed. You might have told me earlier.你本可以早点告诉我的。抱怨责备三neednt have done“neednt +have+过去分词表示“本来不需要做，“做了不必做或不需要做的事，如：I neednt have borrowed the money yesterday.注意didnt need to do表示“没有必要做而实际上也没有做某事。四：can/ could have done:用来谈过去的情况1.在疑问句、否认句中，表示对过去的行为的疑心和不可能，这时它们没有时间上的差异，只是could的语气更弱一些：Who could have ta

11、ken them? He cant have taken it home.2.could have done在肯定句中，表示“那时本来可以 ；差点就要，有时用来进展婉转地批评：He could have told her, but he did not choose to.五should/ ought to have done表示“过去应该做某事却没有做；“should not/ ought not to have+过去分词表示“做了不应该做的事。含有责备或遗憾的意思：You should have come here ten minutes earlier.三、几组情态动词用法的区别一can

12、和be able to的区别。在一般将来时和如今完成时中只能用be able to。can表示具备某种才能，但不一定做事；而be able to表示后天努力设法去做，成功后说明有才能，如：He was able to swim across the river in fifteen minutes.= He managed to swim across the river in fifteen minutes.二must与have tomust强调主观意志，必要性来自说话者的主观意志，“必须。Have to强调客观因素，“不得不。如：He must stop smoking.他必须戒烟。说话人

13、认为他必须You have to go and see the boss.你一定得去见见老板。客观因素注意：must not表示“绝对不可；dont have to或havent got to表示“不必，没必要，两者意思极为不同。三would与used towould可表示反复发生的动作或某种倾向。Used to表示过去的习惯动作或状态，强调如今已不存在。如：She used to work into the night.过去她常工作到深夜。如今不了She would work into the might.以前她常工作到深夜。不表示如今不了【例题精析】例1. Tom, you _ leave

14、 all your clothes on the floor like this!A.wouldnt B.mustnt C.neednt D.may not答案：B 。例2. Where is my pen? I _ it.A. might lose B. need have lost C. must lose D. must have lost答案：D 。 专题测试1.Could I borrow your book? Yes, of course you _ .A. may B. could C. must D. can2. I wonder how he that _ to his pa

15、rents.A. dare to say B. dared say C. dares to say D. didnt dare to say3.Shall I tell him about it? No, you _ . I have told him already.A. neednt B. wouldnt C. shouldnt D. mustnt4. I _ have written to him because he phoned me later.A. ought to B. must C. couldnt D. neednt5.You can hardly swim, can yo

16、u? _ . But my mother said she would teach me.A. Yes, I cant B. No, I cant C. No, I can D. Yes, I can6.Write to me when you get home. _ .A.I must B.I should C.I will D.I can7.Where shall we meet tomorrow? Well.I _come to your house if you like.A. could B. might C. should D. must8. Dont throw the bott

17、les away. They _ in the future.A. may need B. are needed C. can be needing D. might be needed9. He was caught in the rain last night. That _ his cold.A. must bring about B. ought to bring about C. should have brought about D. may have brought about10.I saw Jane in the street yesterday. You _ her. He

18、 is still abroad.A. mustnt see B. cant have seen C.mustnt have seen D.ought not to have seen11.You must phone us every week. Yes, I _ .A. must B. have to C. will D. should12. John, look at the time. _ you play the piano at such a late hour?A. Must B. Can C. May D. Need13. The line is busy. Someone _

19、 the telephone.A. may be using B. may have used C. must have been using D. must be using14. English is a language that many people around the world _ not speak perfectly but at least _ understand.A. may, can B. would, might C. will, must D. could, might15.What are you going to do for your holiday? I

20、m not sure. I _ make a trip to the beach.A. can B. may C. must D. should16.I wonder why Mr. Wang didnt attend the lecture. He _ another one.A. could have B. must have C. might have had D. should have had17. He was taken away by the police. He _ for a robber.A. must be mistaken B. was being mistaken

21、C. must mistake D. must have been mistaken18.Must I be at home at 6 ? No, you _ .A. mustnt B. cant C. neednt D. shouldnt19.I wonder if I _ smoke here. No, you _ . Could you see the sign “No Smokingthere?A. can, neednt B. shall, wont C. must, cant D. may, mustnt20. Tom always did well in all his subj

22、ects, so he _ in the final exam.A. mustnt fail B. couldnt have failed C. ought not to fail D. mustnt have failed21.I didnt go to work yesterday afternoon because my car broke down. You _ mine. I wasnt using it.A. might borrow B. could have borrowed C. can have borrowed D. ought to borrow22. A computer _ think for itself, it must be told what to do.A. cant B. couldnt C. may not D. might not23. I didnt hear the phone. I _ asleep.A. must be B. must have been C. should be D. should have been24. We _ last night, but we went to the concert instead.A. must have studied B. might stu