专四语法第7节--情态助动词

1、专四语法专题第七节：情态助动词 I. 情态助动词考点和知识要点： 情态助动词概述： 情态助动词有 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。 情态助动词知识要点： 1. can / could 2. may / might 3. will, would 4. shall 5. should, ought to 6. must 7. need 8.

2、 dare 9. 情态动词 + 不定式完成式( have done) 1. can / could 1) 表示请求和允许 (Permission) Can I go now? - Yes, you can. / No, you can t. 此时可与 may 互换。在疑问句中还可用 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, I m afraid not. ) 2) 表示能力(体力、知识、技能) (Ability) Can you lift

3、this heavy box? (体力) Mary can speak three Ianguages.(知识) Can you skate?(技能) 表示“能力”时可与 be abIe to 互换。 Can 只有一般现在时和一般过去式；而 be abIe to 则有更多的时态。 I II not be abIe to come this afternoon. 但当表示“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 abIe to go to the party yesterday evening in spite of the heavy ra

4、in. 3) 表示客观可能性(客观原因形成的能力) (Possibility) They ve 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 this be true? This can t be done by him. How can this be true? 2. may / might 1) 表示请求和允许 (Permission) 。 might 比 may 语气

5、更委婉，而不是过去式。否定回答时可用 cant 或 mustn t，表示 “不可以，禁止”。 - Might/ May I smoke in this room? - No, you mustn t. - May/Might I take this book out of the room? - Yes, you can. (No, you can t / mustn t. ) 用 May I. ？征徇对方许可时比较正式和客气，而用 Can I.？在口语中更常见。 2) 表示推测、可能性(不用于疑问句) (Possibility) 。 might 不是过去式，它所表示的可能性比 may 小。

6、He may /might be very busy now. Your mother may /might not know the truth. 3) 用于祈使句，表示祝愿。 May you succeed! 4) may /might.as well 表示“不妨，还是 .的好” ,也可以写作 may /might as well. Since it is raining hard, you may as well stay here. 3. will, would 1) 用于第二人称疑问句中，表示请求、建议等， would 更委婉，不表时态。 Will / Would you pass

7、me the ball, please? 2) 表示意愿( Willingness )、意图( Intention )、决心( Determination )、承诺( Promise) 等，可用于各种人称。 I will never do that again. 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， 且 没有“现已无此习惯”的含义。 During the vacation, he would visit me every other day. The

8、 wound would not heal. 4) 表示估计和猜想。 It would be about ten o clock when she left home. 4. shall 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。 You shall fail if you don t work hard.(警告) He shall have the book when I finish it.( 允诺 ) He shall be pu ni sh

9、ed.(威胁) 5. 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。 I should help her because she is in trouble. You ought 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 。 You should / ought to go to class right away. Should I open the window? 3） 表示推

10、测 should , ought to （ 客观推测 ）, must（ 主观推测 ）。 He must be home by now. （ 断定他已到家 ） He ought to/should be home by now.（ 不太肯定 ） This is where the oil must be.（ 直爽 ） This is where the oil ought to/should be.（ 含蓄 ） Uncertain might may could can should ought to would will Certain must 6. must, have to 1） 表示必

11、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 mustn t （禁止，不准），而用 needn t, don t have to （不必） - Must we hand in our exercise books today? - Yes, you must. - No, you don t have to / you needn t. 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。 He play isn t interesting, I real

12、ly must go now. 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） You re Tom s good friend, so you must know what he likes best. Your mother must be waiting for you now. 7. 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。 How dare you say I m unfair? He daren t speak English bef

13、ore such a crowd, dare he? If we dared not go there that day ， we couldn 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。 You needn t come so early. - Need I finish the work today? - Yes, you must. / No, you needn t. 3) dare 和 need 作实义动词用时， 有人称、时

14、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 的不定式。 而 need 后面只能接带 to 的不定式。 I dare to swim across this river. He doesn t dare (to) answer. He needs to finish his homework today. 8. will, would 1) 用于第二人称疑问句中，表示请求、建议等， would 更委婉，不表时态。 Will / Would you pass me the ball, please? 2) 表示

15、意愿( Willingness )、意图( Intention )、决心( Determination )、承诺( Promise ) 等，可用于各种人称。 I will never do that again. 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，且 没有“现已无此习惯”的含义。 During the vacation, he would visit me every other day. The wound would not heal. 4)

16、表示估计和猜想。 It would be about ten o clock when she left home. 9. 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。 You could have done better, but you didnt try your best. (虚拟语气) He can t have been to that t own. (推测) Can he have got t

17、he 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。 He may not have finished the work . 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。参看 1) can / could +

18、 have done 表示推测。 You must have seen the film Titanic. 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。 You ought to / should have helped him. (but you di

19、dn t.) 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. II. 情态助动词专四真题模拟题 1. Amon

20、g the four sentences below, Sentence _ expresses the highest degree of possibility. A. It may take a long time to find a solution to the problem. B. It might take a long time to find a solution to the problem. C. It could take a long time to find a solution to the problem. D. It should take a long t

21、ime to find a solution to the problem. 2. Which of the following italicized words does NOT indicate willingness? A. What will you do when you graduate? B. They will be home by now. C. Who will go with me? D. Why will you go there alone? 3. When the sentence “Shall I drive you to the airport first? ”

22、 eisetcuhr,ned into indirect sp which of the following is most appropriate? A. He agreed to drive me to the airport first. B. B. He offered to drive me to the airport first. C. He advised me to go to the airport first. D. He suggested that I drive to the airport first. 4. Which of the following sent

23、ences indicates POSSIBILITY? A. The moon cannot always be at the full. B. You cannot smoke inside the building. C. He cannot come today. D. She cannot play the piano. 5. Which of the following sentences a fact? A. Mary and her son must be home by now. B. Careless reading must give poor results. C. H

24、e must be working late at the office. D It s getting late, and I must leave now. 6. Which of the following best explains the meaning of Shall we buy the tickets first ”? A He said that we were going to buy the tickets first B He requested that we buy the tickets first C He suggested that we buy the

25、tickets first D He advised us to buy the tickets first 7. Which of the following sentences expresses WILLINGNESS? A By now she will be eating dinner B I shall never do that again C My brother will help you with the luggage D You shall get a promotion 8. The sentence that expresses OFFER is _ . A. Il

26、l get some drinks. Whatll you have? B. Does she need to book a ticket now? C. May I know your name? D. Can you return the book next week? 9. Nancys gone to work but her cars still there. She _ by bus. gone one A. must have gone C. ought to have gone B. should have D. could have 10. Aren t you tired?

27、 I _ _ you had done enough for today. A. should have thought B. must have thought C. might have thought D. could have thought 11. Iwent ther e in 1984, and that was the only occas ion when I the iourney i n exactly two days. A. must take B. must have made C. was able to make D. could make 12. Which

28、of the following sentences expresses probability? A. You must leave immediately. B. You must be feeling rather tired. C. You must be here by eight oclock. D. You must complete the reading assignment on time. 13. She _ fifty or so when I first met her at the conference. A. must be B. had been C. coul

29、d be D. must have been 14. You borrow my notes provided you take care of them, told my friend. I A. could B. should C. must D. can 15. I am surprised_ this city is a dull place to live in. A. that you should think B. by what you are thinking C. that you would think D. with what you were thinking 16.

30、 Loud speakers were fixed in the hall so that everyone_ an opportunity to hear the speech. A. ought to have B. must have C. may have D. should have 17. You _ Mark any thi ng about it. It was none of his bus in ess. a. needn t have told b. needn t tec. mustn t have toldd. mustn t tell 18. He _ unwise

31、ly, but he was at least trying to do something helpful. a. may have acted b. must have acted c. should act d. would act 19. The meeting s been canceAnh pocket. ” 23. Since the weather is fine we _ walk for a while . A. may B. must C. might as well D. will 24. If your car _ any atte nti on duri ng th

32、e first 12 mon ths , take it to an authorized dealer. A. shall n eed B. should n eed C. would n eed D. will n eed 25. As it turned out to be a small house party, we _ so formally.all that work. a. n eed to do b. n eed have c. n eed n t have doned. n eeded not to do 20. “ She must be in the dormitory

33、 ” “ No, be there. I saw her in the classroom a mi ago. a. must n t b. can t c. could d. wouldn t 21. He the 8:20 bus because he did n t leave home till 8:25. a. could t have caught b. ought to have caught c. should t have caught d. must not have caught 22. The door was ope n. ft open. I had locked

34、it myself and the key was in my A. can tbe B. must n tbe C. can have bee n D. mustn have been a. need not have dressed up b. must not have dressed up c. did not need to dress up d. must not dress up 26. Which of the following sentence express WILLINGNESS? A. By now she will be eating dinner. B. I sh

35、all never do that again. C. You shall get a promotion. D. My brother will help you with the luggage. 30. Is there a movie on in the cinema tonight ？ There_ be. I will phone the cinema and find it out. A. might B. should C. can D. could 31. He didn t agree with me at first, but I _ persuade him to si

36、gn the agreement later. A. could B. might C. should D. was able to 32. You _ out last night. I called you several times, but nobody answered. A. must have been B. must be C. might have been D. could be 33. Oh, Jane, you ve broken another glass. You ought _ when you washed it. A. be careful B. to car

37、e C. have cared D. to have been careful 34. We _ booked. Look, this restaurant is almost empty. A. must have B. can t haveC. should have D. needn t have 35. Do you still remember the day when we went to the Great Wall ？ I can t remember it well, but _ sometime last autum？n27. Which of the following

38、bes t explains the meaning of A. He said that we were going to buy the tickets first. B. He requested that we buy the tickets first. C. He suggested that we buy the tickets first. D. He advised us to buy the tickets first. 28. Which of the following sentences expresses A. You must leave immediately.

39、 B. You must be feeling rather tired. C. You must be here by eight o clock. D. You must complete the reading assignment on time. 29. Someone is knocking at the door. _ it be Venis ？ No, it _ be her ； she left for New York this morning. A. Can; mustn t B. Might; can tC. May; doesn Shall we buy the ti

40、ckets first ”? probability ”? t D. Can; can t A. might it be B. could it have been C. could it be D. must it have been 36. I can t get through to the general manager The line is busy. Someone _ the telephone. A. must use B. uses C. must have been using 37. It is rather cold here. Shall we light a fi

41、re ？ No, we _ because things are easy to catch fire. A. won t B. can t C. mustn t 38. Listen! The fire engine is roaring. There _ be a fire somewhere. A. should B. must C. will D. ought to 39. “ The interest _ be divided into five parts, according to the agreement made by both sides, declared the judge. A. may B. should C. must D. shall 40