1、第十章 情态动词,情态动词的语法特征 1） 情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。 2） 情态动词 除ought 和have 外，后面只能接不带to 的不定式。 3） 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。 4） 情态动词没有非谓语形式，即没有不定式，分词，等形式,不带to不定式的情态动词的6种形式,以Will 为例：,1. John will be 40 next month.一般式 2. It will be getting dark soon.进行式 3. Ill have been here for 3years next June
2、.完成式 4.Be the end of next month, he will have been working here for 5years.完成进行式 5.If it rains, the match will be cancelled.一般式被动 6. By the end of next week, all the work will have been finished.完成式被动,一、各个情态动词用法归纳,can和 could,1 . 表示“能力” I can swim , but my sister cant.,2表示“许可”、“请求” Can I go with you
3、? (请求) Father said I could go to cinema. (表示过去的许可) You cannot smoke in the meeting room. (cannot 表示“禁止”) Could I use your phone?Yes, of course you can.肯定回答，不能用could ，一般是Yes, please. Thanks.,3表示“理论上或逻辑上的可能” Anybody can make mistakes. (只表示理论上的可能性) An accident can happen if you do this. (表示事情肯定会发生),4“猜
4、测”（主要用于否定句和疑问句）： He cant be at home. (否定句) Can the news be true ? (疑问句),与be able to 的区别： can 只有现在和过去时态，强调能力； be able to有各种时态，表示“一时“的能力，强调结果。 Mary can play the piano .She has been able to play it since she was 5. Yesterday I was able to get home before the heavy rain.,may 和might,1表示“许可” You may take
5、a walk. Students may not make noise in the library. (may not 表示不许可或禁止)May I come in? 否定回答No, you mustnt. /cannot. 也可以 may not肯定回答sure, certainly, of courseMight I trouble you for a light? “You may indeed.“,2.表示“事实上的可能性“ It may rain tomorrow. (表示可能会发生) Electric irons could be dangerous,they might giv
6、e you a severe shock.,3.“预测” Sam might have taken the money, but it seems unlikely.,must,1.表示“必须”、“务必”： We must obey orders. Must I pay now ? 肯定回答 Yes, you must 否定回答 No, you neednt 或 No, you dont have to,2.表示“预测“ (必定，必会) 一般用于肯定句。可用于否定一般疑问句。There must be a mistake. Mustnt there be another reason for
7、his behavior?,3. 偏偏 Our boy must do the opposite to what we ordered.Just when I was busy , she must come and chat,shall,1.用于第一、三人称，表示征求对方的意见 Shall we talk? Shall he come to see you ?,2.用于第二、三人称，表示“命令、允诺、警告、决心“等Each member shall wear a name card. No one shall stop me. You shall have the book when I f
8、inish reading it.He shall get his allowance.,Should,1.表示“必须”： I should answer his letter as soon as possible. You shouldnt judge a man always by the clothes. (shouldnt劝告),2.猜测，“估计 应该” That should be Janet coming upstairs now. 正在上楼的该是珍妮特。,Will和 Would,1.表示“意愿” I will call you as soon as possible. Who
9、will do the job ? He would not let me try .,2表示“请求” Will you kindly tell me the way to the post office ? Would you give me your address ? (用 would 比 will 表示更客气),3.表示“预测”或“习惯性”： That would be his mother. (would be 表示肯定是) He will sit there hour after hour looking at the river. He would come to see me
10、when he was in London.,used to 与would的区别 used to表示过去情况与现在不同; would只单纯表示过去的情况,People used to think that the earth was flat. She would go out for a walk in the morning when she was in the country.,ought to,1.表示“应该” You ought to go to see the doctor. (ought to 的语气比must 弱)You oughtnt (ought not) to smok
11、e so much. Ought you to smoke so much?,2.表示“预测”，婉转,比must语气弱 They ought to be there by now.,should 和ought to的区别,含义大致相同， ought to 强调在客观上（法律，章程和道义），比should语气强。 should强调主观上，表示主语的职责和义务或说话人的劝告。,You ought to go and see Mary tomorrow. You shouldnt judge a man always by the clothes.,need和dare 用作情态动词时，主要用在否定句
12、、疑问句中，用作实义动词时, 可用于各种句式。 Need I come? Yes , you must./No,you neednt. You neednt telephone him now. She dare not go out alone at night. We should dare to give our own opinion. We need to tell them the news. 注意：dare用作实义动词时，其否定句中的to可保留也可省略。 She doesnt dare to climb the tree. She doesnt dare climb the tr
13、ee.,二、情态动词的完成式和进行式 modal verb+ have done: 对过去发生的事情进行评价、猜测，表示“应当已经、想必已经、本来可以做但未做” I should have finished the work earlier. He isnt here. He must have missed the train. Where can (could) he have gone? You could(might) have been more careful. You ought to have come,but why didnt you? modal verb+be doin
14、g: 对正在发生的事情进行评价、猜测，表示“想必正在、可能正在、应当正在” Its 12 oclock .They must be having lunch. They may be discussing the problem. He cant be telling the truth. She shouldnt be working like that.She is still so weak.,三、would rather和had better的用法,1、 would rather 表示“宁愿” would rather + do 动词原形would rather not + do wo
15、uld rather than+ do 宁愿而不愿。would rather + that (从句)+did还有would sooner, had rather, had sooner都表示“宁愿“、“宁可“的意思。 If I have a choice, I had sooner not continue my studies at this school. I would rather stay here than go home. = I would stay here rather than go home. 典型例题 -Shall we go skating or stay at h
16、ome? -Which _ do? A. do you rather B. would you rather C. will you rather D. should you rather 答案B。本题考查情态动词rather的用法，would rather +do sth 意为“宁愿“，本题为疑问句，would 提前，所以选B,2、 had better 表示“最好” had better 相当于一个助动词，它只有一种形式，它后面要跟动词原形。 had better do sth had better not do sth It is pretty cold. Youd better put
17、 on my coat. Shed better not play with the dog.you had better not wake me up when you come in.had better have done sth表示与事实相反的结果，意为“本来最好“。 You had better have come earlier .,情态动词专项练习 I hear youve got a set of Australian coins. I have a look? Yes, certainly.A. Do B. May C.Shall D. Should 2. He seldom
18、 listens to others. He answer for what he has done.A. shall B. will C. can D. would 3. May I leave the office before 5 oclock in the afternoon? No, Im afraid you .A. neednt B. shouldnt C. mustnt D. wont 4. Shall I tell John about it? No, you . I dont know his telephone number.A. neednt B. wouldnt C.
19、 mustnt D. shouldnt 5. Mr Bush is on time for everything. How it be that he was late for the opening ceremony?A. can B. should C. may D. must,A,C,B,A,A,6. The traffic light is red, so I stop my car.A. must B. have to C. can D. mustnt 7. What happened to the young trees we planted? The trees well, bu
20、t I didnt water them.A. might grow B. neednt have grown C. would grow D. would have grown 8. I was really anxious about you. You home without a word.A. mustnt leave B. shouldnt have left C. couldnt have left D. neednt leave 9. Tom show his exam results to his parents.A. dare not B. dared C. dare to
21、D. dares not to 10. She the film. She knows nothing about it.A. cant see B. cant have seen C. must see D. mustnt have seen,B,D,B,A,B,11. They must have been here the day before yesterday, ?A. mustnt they B. didnt they C. mustnt have they D. had they 12. I didnt see her yesterday. Oh, but you .A. mus
22、t have B. ought to C. should have D. cannot have 13. Must I take a bus ? No, you . You can walk from here.A. must not B. dont C. dont have to D. had better not to 14. Will you stay for lunch? Sorry, . My brother is coming to see me.A. I mustnt B. I cant C. I neednt D. I wont 15. I often go fishing w
23、hen I lived in the countryside.A. should B. would C. could D. might 16. Could I use your telephone? Yes, of course you .A. could B. will C. can D. might,B,C,C,B,B,C,17. I cant get through to the general managers office anyhow. The line is busy. Someone the telephone.A. must use B. uses C. must have
24、been using D. must be using 18. Do you think he will do me a favor? As far as I know, he is the last one to help others.He_be prepared to give you a hand, though.A. might B. must C. can D. should 19. Even though Id hurt my leg, I swim back to the river bank.A. could B. might C. had to D. was able to
25、 20. You go to the party if you dont finish your homework first.A. wont B. dont C. oughtnt D. shant 21. It is rather cold here. Shall we light a fire? No, we because things are easy to catch fire.A. wont B. cant C. mustnt D. neednt 22. Very loud noise make people ill or drive them mad.A. should B. can C. need D. must,B,C,D,D,A,D,
