情态动词讲解及练习

1、情态动词讲义和专项练习情态动词有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, could1) 表示能力（体力、知识、技能）。e.g. Can you lift this heavy box?（体力）Mary can speak three languages.（知识）Can you skate?（技能）此时可用be able to代替。ca

2、n只有一般现在时和一般过去式；而be able to则有更多的时态。e.g. 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：e.g. He was able to go to the party yesterday evening in spite of the heavy rain.Although he cant swim, yet he was able to cross the river.2) 表示请求和允许。e.g. -Can I go now? - Yes, you c

3、an. / No, you cant. 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。e.g. - 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）。e.g. Theyve changed the timetable, so we can go by bus instead.Even experienced teachers can make mistakes.4) 表示推测（惊讶、怀疑

4、、不相信的态度），用于疑问句、否定句和感叹句中。e.g. Can this be true?This cant be done by him.How can this be true?5）“can + have done”主要用于否定句和疑问句中，表示对过去发生的行为怀疑或不肯定。e.g. He cannot have been to that town.Can he have got the book?“could + have done”表示虚拟语气。e.g. But for your help, we couldnt have finished the task before the d

5、eadline.You could have achieved better results but you wasted the valuable time.6）习惯用法：cannot too “再也不过分”e.g. You cannot be too careful in the choice of your friends.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”。e.g. -Might/ May I smoke in this room? - No, you mustnt.

6、- May/Might I take this book out of the room?- Yes, you can. (No, you cant / mustnt. )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）用于祈使句，表示祝愿。e.g. May you succeed!3) 表示推测、可能性（表示此意时，不用于疑问句）。might不是过去式，它所表示的可能性比may小。e.g. He may /might be very busy now.Your mother may /might not know the truth.4）“may / mi

7、ght + have done”表示对过去行为的推测。e.g. Without the heavy traffic, we might have caught the train.5）习惯用法：may / might as well + do “不妨”e.g. You might as well have an another try.三、 must, have to1) 表示必须、必要。e.g. 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, dont have to（不必）.e.g. - Must we h

8、and 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。e.g. The play isnt interesting, I really 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）e.g. Youre Toms good friend, so you must kn

9、ow what he likes best. Your mother must be waiting for you now.表示肯定推测的否定句，用cannote.g. This cannot be your pen.4）“must + have done”对过去行为的肯定推测，否定句用cannot have done.e.g. It must have been rainy yesterday, wasnt it?It must have rained yesterday, didnt it?5）have got to是have to 的口语形式。e.g. You havent got t

10、o go to school today, have you?6）must “偏偏”e.g. Why must it rain on Sunday?We were going to see a movie, but it must rain yesterday.四、 dare, need1) 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。e.g. How dare you say Im unfair?He darent speak English before such a crowd, dare he?If we dared not go there

11、that day, we couldnt 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。e.g. You neednt come so early. - 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的不定式

12、。而need后面只能接带to的不定式。e.g. I dare to swim across this river.He doesnt dare (to) answer.He needs to finish his homework today.4）“neednt + have done”表示虚拟语气，本不必做某事而事实上却做了。e.g. You neednt have waited for me.5）need doing = need to be done.e.g. The washing machine needs repairing. = The washing machine needs

13、 to be repaired.6）“I dare say”意为“我猜测”e.g. I dare say he will come. 五、 shall, should, ought to1) shall 用于第一人称，征求对方的意见。e.g. What shall we do this evening?2) shall 用于第二、三人称的肯定句，表示说话人给对方的命令、警告、允诺或威胁。e.g. You shall fail if you dont work hard.(警告)He shall have the book when I finish it.(允诺)He shall be pun

14、ished.(威胁)3）shall用于第一，第三人称疑问句中，表示说话人征求对方的意见或向对方请示。e.g. Shall we begin our lesson?When shall we be able to leave the hospital?4）should, ought to表示“应该”，ought to表示义务或责任，比should语气重。e.g. I should help her because she is in trouble.You ought to take care of the baby.5) 表示劝告、建议和命令。should, ought to可通用，但在疑问句

15、中常用should。e.g. You should / ought to go to class right away.Should I open the window?6) should表示主观推测，“估计”“按道理应该”e.g. He ought to/should be home by now.They should finish it by now.7）“should + have done”用于虚拟语气，本应该做某事而实际上并未做某事。 Shouldnt have done本不该做而做了e.g. You should have arrived here 5 minutes earli

16、er.8）特殊用法：“竟然”“居然”表示说话人感到意外，赞叹，愤怒，惊异等感情。e.g. You cant imagine the gentleman should be a thief.e.g. I dont know why you should think I did it.“倒是”，用于第一人称时表示说话人的一种谦逊，客气，委婉的语气。e.g. I should think it would be better to try it again.I should advise you not to do that.六、 will, would1) will表示请求、建议等，would更委

17、婉。e.g. Will / Would you pass me the ball, please?2) will表示意志、愿望和决心。e.g. 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。e.g. During the vacation, he would visit me every other day.The wound would not heal.4) would表示估计和猜想

18、。 e.g. It would be about ten oclock when she left home.5）would用在虚拟语气中（参考虚拟语气语法）。e.g. If it should rain, the crop would be saved.七、 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未能做某事”，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。e.g. You could have done better, but you didnt try your best.

19、 （虚拟语气）He cant have been to that town.（推测）Can he 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。might所表示的可能性比may小。e.g. 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

20、、否定形式用can，cant。can / could + have done表示推测。e.g. 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。e.g. 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。e.g. You ought to / shoul

21、d have helped him. (but you didnt.)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”。e.g. 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。e.g. He will have arrived b

22、y now.情态动词专项练习1. When _ he leave the hospital? I asked the doctor.A. will B. shall C. can D. may2.- They have not finish the work up to now.-Well, they _A. should have B. should C. ought to D. ought have3. Since it is already midnight, we_.A. had better leaving B. ought to have leave C. should take

23、our leave D. might as well leave4._ you be happy!A. May B. Can C. Must D. Would5. Must we come tomorrow?A. No, you cant B. No, you neednt C. No, you mustnt D. No, you may not6. You _miss the lesson, though we_ have it on Thursday.A. mustnt.neednt B. neednt.mustnt C. mustnt.mustnt D. neednt.neednt7.

24、To succeed in a difficult task,_.A. one needs to work hard B. to work hard is neededC. you need be a hard working person D. to work hard is what one needs8. In case I_, I would try again.A. will fail B. would miss C. should fail D. shall miss9. Some people feel that handguns_.A. should control B. sh

25、ould be controlled C. must be controlling D. can be control10. _ open the door for you ?A. Would you like that I B. Do you want that I C. Will I D. Shall I11. He doesnt have to work tomorrow, but you have got to,_ you?A. dont B. havent C. havent got D. cant12. You _wake me up when I fall asleep,_ yo

26、u?A. havent better; have B. would not rather; would C. had better not; should. D. had not better; must13-Why! I couldnt get you on the phone this morning. -We _tennis in the yard when you phoned me.A. could be playing B. must be playing C. must have been playing D. should have played14. -We didnt se

27、e him at the lecture. -Neither did anybody else. He _ it.A. may not have attended B. mustnt attend C. cant have attended D. couldnt attend15. -I came here by taxi and the driver charged me 50 Yuan. -Really? You _have come by bus.A. could B. must C. may D. should16. -Do you still remember when we wen

28、t to the great wall -I cant remember it well, but_ it have been sometimes last may?A. should B. must C. could D. would17. -I wonder why Mr lin didnt come to work. -He _have been ill.A. neednt B. should C. might D. can18.-No one passed the mathematics last night. -I guess we_ the exercises last night

29、.A. could review B. should review C. might review D. should have reviewed19. She_the hospital so soon, for she hasnt yet recovered.A. wouldnt have left B. shouldnt have left C. neednt have left D. hadnt 20. Why didnt you tell me there was no meeting today? I _ all the way. Here through the heavy sno

30、w.A. neednt have driven B. cant have driven C. must have driven D. shouldnt have driven21.I thought youlike something to read, so I have brought you some books. A.may B.might C.could D.must 22.You to the meeting this afternoon if you have something important to do.A. neednt to come B. dont need come

31、 C. dont need coming D. neednt come 23. Heyou more help, even though he was very busy. A. might have given B. might give C. may have given D. may give 24.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 25. The reason why they leave was

32、nt explained to us.A. had B. had to C. must D. might 26. I searched for my wallet and it wasnt there. I thought I it at home. A. left B. have left C. might have left D. could have left 27. I asleep because it took me a long time to realize that the telephone was ringing.A. could have fallen B. shoul

33、d have fallen C. must have fallen D. mustnt have fallen 28. 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 29. I want to go to the chemists, but you go with me.A. need not B. must not C. need D. must 30. I thought it

34、over, but come to no conclusion. A. can B. could C. should D. would 31. What we get seems better than what we have. A. can B. could C. cant D. couldnt 32.My goodness! Ive just missed the train. Thats too bad. I am sure you it, if you had hurried. A. could have caught B. had caught C. would catch D.

35、could catch 33. Look! What youve done! You more careful.A. may be B. had toC. should have been D. would be 34. I repeat the question? A. Shall B. Will C. Do you want that D. Do 35. Professor Li, many students want to see you. they wait here or outside!A. Do B. Will C. Shall D. Are 36. You read that

36、book if you dont want to. A. havent B. cant C. mustnt D. neednt 37. Johnny, you play with the knife; you hurt yourself.A. wont; cant B. cant; shouldnt C. shouldnt; must D. mustnt; may 38. Its nearly seven oclock. Jack be here at any moment. A. must B. need C. can D. should 39. There were already 5 p

37、eople in the car, but they managed to take me as well. It a comfortable journey. A. cant be B. shouldnt beC. couldnt have been D. mustnt have been 40. Tom ought not to me your secret, but he meant no harm. A. have told B. tellC. be telling C. having told 41. Everyone is here. we start the meeting? A. Can B. Must C. Should D. Shall 42.