1、情态动词用法归纳0 情态动词用法归纳 情态动词用法归纳 情态动词有 can (could), may (might), must, have to, shall (should, will (would), dare (dared), need (needed), ought to 等。 情态动词无人称和数的变化； 不能单独使用， 必须与其后的动词原形构成谓语 一、 can, could 1) 表示能力（体力、 知识、 技能）。 Can you lift this heavy box?（体力） Mary can speak three languages.（知识） Can you skate?
2、（技能） 此时可用 be able to 代替。 Can 只有一般现在时和一般过去式； 而 be able to 则有更多的时态。 Ill not be able to come this afternoon. 当表示经过努力才得以做成功某事 时应用 be able to， 不能用 Can。 如： He was able to go to the party yesterday evening in spite of the heavy rain. 2) 表示请求和允许。 -Can I go now? - Yes, you can. / No, you cant. 此时可与 may 互换。 在
3、疑问句中还可用 could, might 代替， 不是过去式， 只是语气更委婉， 不能用于肯定句和答语中。 - Could I come to see you tomorrow? - Yes, you can. ( No, Im afraid not. ) 3) 表示客观可能性（客观原因形成的能力）。 Theyve changed the timetable, so we can go by bus instead. This hall can hold 500 people at least. 4) 表示推测（惊讶、 怀疑、 不相信的态度）， 用于疑问句、 否定句和感叹句中。 Can thi
4、s be true? This cant be done by him. How can this be true? 二、 may, might 1) 表示请求和允许。 might 比 may 语气更委婉， 而不是过去式。 否定回答时可用 cant 或 mustnt， 表示不可以， 禁止。 -Might/ May I smoke in this room? - No, you mustnt. - May/Might I take this book out of the room? - Yes, you can. (No, you cant / mustnt. ) 用 May I.？ 征徇对方
5、许可时比较正式和客气， 而用 Can I.？ 在口语中更常见。 2） 用于祈使句， 表示祝愿。 May you succeed! 3) 表示推测、 可能性（不用于疑问句）。 might 不是过去式， 它所表示的可能性比 may 小。 1 He may /might be very busy now. 2 Your mother may /might not know the truth. 三、 must, have to 1) 表示必须、 必要。 You must come in time. 在回答引出的问句时， 如果是否定的， 不能用 mustnt （禁止， 不准）， 而用 neednt,
6、dont have to（不必） . - Must we hand in our exercise books today? - Yes, you must. - No, you dont have to / you neednt. 2) must 是说话人的主观看法， 而 have to 则强调客观需要。 Must 只有一般现在时， have to 有更多的时态形式。 1 he play isnt interesting, I really must go now. 2 I had to work when I was your age. 3) 表示推测、 可能性（只用于肯定的陈述句） 1
7、Youre Toms good friend, so you must know what he likes best. 2 Your mother must be waiting for you now. 四、 dare, need 1) dare 作情态动词用时, 常用于疑问句、 否定句和条件从句中, 过去式形式为 dared。 1 How dare you say Im unfair? 2 He darent speak English before such a crowd, dare he? 3 If we dared not go there that day， we couldn
8、t get the beautiful flowers. 2) need 作情态动词用时, 常用于疑问句、否定句。 在肯定句中一般用 must, have to, ought to, should 代替。 1 You neednt come so early. 2. - Need I finish the work today? - Yes, you must. / No, you neednt. 3) dare 和 need 作实义动词用时， 有人称、 时态和数的变化。 在肯定句中， dare 后面常接带 to 的不定式。 在疑问句和否定句中， dare 后面可接带 to 或不带 to 的不
9、定式。 而 need后面只能接带 to 的不定式。 1. I dare to swim across this river. 2. He doesnt dare (to) answer. 3. He needs to finish his homework today. 五、 shall, should 1) shall 用于第一人称， 征求对方的意见。 What shall we do this evening? 2) shall 用于第二、 三人称， 表示说话人给对方的命令、 警告、 允诺或威胁。 1. You shall fail if you dont work hard.(警告) 2
10、. He shall have the book when I finish it.(允诺) 3. He shall be punished.(威胁) 六、 will, would 1) 表示请求、 建议等， would 更委婉。 Will / Would you pass me the ball, please? 2) 表示意志、 愿望和决心。 1. I will never do that again. 2. They asked him if he would go abroad. 3) would 表示过去反复发生的动作或某种倾向。 would 表示过去习惯时比 used to 正式，
11、且没有现已无此习惯 的含义。 1. During the vacation, he would visit me every other day. 2. The wound would not heal. 4) 表示估计和猜想。 It would be about ten oclock when she left home. 七、 should, ought to 1) should, ought to 表示应该， ought to 表示义务或责任， 比 should 语气重。 1. I should help her because she is in trouble. 2. You oug
12、ht to take care of the baby. 2) 表示劝告、 建议和命令。 should, ought to 可通用， 但在疑问句中常用 should。 1. You should / ought to go to class right away. 2. Should I open the window? 3) 表示推测 should , ought to (客观推测), must(主观推测)。 1.He must be home by now. (断定他已到家) 2.He ought to/should be home by now.(不太肯定) 3. This is whe
13、re the oil must be.(直爽) 4. This is where the oil ought to/should be.(含蓄) 八、 情态动词+不定式完成式（have done） 1) can / could + have done 在肯定句中表示本来可以做而实际上能做某事， 是虚拟语气； 在疑问句或否定句中表示对过去行为的怀疑或不肯定, 表示推测。 1. You could have done better, but you didnt try your best. （虚拟语气） 2. He cant have been to that town.（推测） 3. Can h
14、e have got the book?（推测） 2) may / might +不定式完成式（have done） 表示对过去行为的推测。 不能用于疑问句中， 没有虚拟语气的用法。 Might 所表示的可能性比 may 小。 1. He may not have finished the work . 2. If we had taken the other road, we might have arrived earlier. 3） must +不定式完成式（have done） 用于肯定句中， 表示对过去行为的推测。 意为一定、 想必。 其疑问、 否定形式用 can，cant 代替。
15、参看 1) can / could + have done 表示推测。 1. You must have seen the film Titanic. 2. He must have been to Shanghai. 4） should +不定式完成式（have done） 用于肯定句中， 表示对过去行为的推测。 He should have finished the work by now。 表示本应该做而实际上没有做某事， 其否定式表示某种行为本不该发生却发生了。 可以与 ought to +不定式完成式（have done） 互换。 1. You ought to / should h
16、ave helped him. (but you didnt.) 2. She shouldnt have taken away my measuring tape, for I wanted to use it. 5) neednt +不定式完成式（have done） 表示本来不必做而实际上做了某事。 You neednt have watered the flowers, for it is going to rain. 6) will +不定式完成式（have done） 主要用于第二、 三人称， 表示对已完成的动作或事态的推测。 He will have arrived by now
17、. 情态动词练习题 . 单项选择(45%) 1. I thought you like something to read, so I have brought you some books. A. may B. might C. could D. must 2. You to the meeting this afternoon if you have something important to do. A. needn t to come B. don t need come C. don t need coming D. needn t come 3. He you more help
18、, even though he was very busy. A. might have given B. might give C. may have given D. may give 4. I help you with some shoes, madam? Yes, I would like to try on those brown ones. A. Will B. Should C. May D. Must 5. The reason why they leave wasn t explained to us. A. had B. had to C. must D. might
19、6. I searched for my wallet and it wasn t there. I thought I it at home. A. left B. have left C. might have left D. could have left 7. I asleep because it took me a long time to realize that the telephone was ringing. A. could have fallen B. should have fallen C. must have fallen D. mustn t have fal
20、len 8. The only thing that really matters to the children is how soon they return to their school. A. can B. must C. have to D. ought to 9. I want to go to the chemist s, but you go with me. A. need not B. must not C. need D. must 10. I thought it over, but come to no conclusion. A. can B. could C.
21、should D. would 11. What we get seems better than what we have. A. can B. could C. can t D. couldn t 12. My goodness! I ve just missed the train. That s too bad. I am sure you it, if you had hurried. A. could have caught B. had caught C. would catch D. could catch 13. Look! What you ve done! You mor
22、e careful. A. may be B. had to C. should have been D. would be 14. I repeat the question? A. Shall B. Will C. Do you want that D. Do 15. Professor Li, many students want to see you. they wait here or outside! A. Do B. Will C. Shall D. Are 16. You read that book if you don t want to. A. haven t B. ca
23、n t C. mustn t D. needn t 17. Johnny, you play with the knife; you hurt yourself A. won t; can t B. can t; shouldn t C. shouldn t; must D. mustn t; may 18. It s nearly seven o clock. Jack be here at any moment. A. must B. need C. can D. should 19. There were already 5 people in the car, but they man
24、aged to take me as well. It a comfortable journey. A. can t be B. shouldn t be C. couldn t have been D. mustn t have been 20. Tom ought not to me your secret, but he meant no harm. A. have told B. tell C. be telling C. having told 21. Everyone is here. we start the meeting? A. Can B. Must C. Should
25、D. Shall 22. I parked my car right here but now it s gone. It . A. must be stolen B. may be stolen C. must have stolen D. must have been stolen 23. He the work yesterday, but he didn t. A. must have finished B. need have finished C. finished D. should have finished 24. He did not pass the examinatio
26、n. As a good student, he . A. mustn t have failed B. may not have failed C. needn t have failed D. shouldn t have failed 25. it be true that Albert passed the test in geography? A. May B. should C. Could D. would 26. You lead a horse to the water but you not make it drink. A. will; can B. may; can C
27、. may; dare D. dare; can 27. Must we finish the composition in class? No, you . A. needn t B. mustn t C. won t D. shouldn t 28. Her eyes were red. She . A. must cry B. must be cried C. must have been crying D. may cry 29. Mary his letter, otherwise she would have replied before now. A. has received
28、B. must receive C. couldn t have received D. shouldn t have received 30. I told Sally how to get here, but perhaps I for her. A. had to write it out B. must have written it out C. should have written it out D. ought to write it out . 用所给动词的适当形式填空(10%) Hello. Gerry speaking. Hello, Gerry. It s me Joh
29、n here. Why aren t you here at the meeting? Well, I m terribly sorry, but I m not feeling very well. Is that all? We thought you might (have) an accident or (forget) the day or something. No, I m sorry. I was sick all night. I think it must (be) the fish I ate last night. Well, I think you should at
30、 least (phone) Kate and (tell) her you weren t coming to the meeting. Yes, I suppose I should (do) so. I m sorry about that. Anyway, I think I ll be able to get in to work tomorrow. OK, Take care and don t eat any more fish. I won t. Thanks for calling. That s all right. . 用 would, should, must , ha
31、ve to 填空 (20%) 1. I have not a raincoat with me. That s why I wait until the rain stops. 2. you be so kind as to keep an eye on my house while I am away? 3. It is important that I see him at once. 4. the pain return， take one of these pills. 5. They didn t dare to leave the train lest they be attack
32、ed by wolves. 6. He ordered that Tom leave the house at once. 7. The last bus has left. We walk home. 8. The weather was bad. We wait for two hours at the airport before we took off. 9. You come and see us sometime. 10. The letter be translated into English. . 把下列句子译成英语 (25%) 1. 她一定把钥匙丢了. 2. 他们一定走了, 可是应当给我留一个条子呀! 3. 你本不必要把整个课文都译成汉语. 4. 我是可能早一些来的, 可是我在路上碰到一个朋友. 5. 下一次你应该更小心些 答案 . 1.B 2.D 3.A 4. C 5. B 6. C 7. C 8. A 9. A 10. B 11.C 12.A 13.C 14.
