补充强调：推测的句型特点(对某一次的推测句型有两部分：语气和时态)(1)语气部分：(以下情态动词语气由强至弱)肯定句：must、may might ( =could)否定句：can，t ( =couldn 't )、mayn t> mightn 't疑问句：can> could (语气更加委婉不确定(2)时态部分：have done 表示对过去的推测be doing 表示对正在进行的推测be表示对现在的推测语气部分写在前时态部分写在后，组合在一起就是推测(-)情态动词表推测的三种句_能用于表推测的情态动词:must, can, could, will, would, may, might, should, ought to1. 在肯定句中一般用must (一定)，may (可能)，might / could (也许，或许)。
(1)He must/may/might know the answer to this question? 他一定/可能/也许知道这个问题的答案。
(2)It is cold in the room・ They must have turned off the heating・屋里很冷，他们肯定把暖气关了。
2. 否定句中用can't / couldn 't (不可能)，may not/might not (可能不)。
(1)It can J t/couldn 't be the headmaster・ He has gone to America.这不可能是校长，他去美国了。
(2)He may not/might not know the scientist.他也许不认识那位科学家。
3. 疑问句中用can /could (能..?)。
(1) Could he have finished the task?他可能把任务完成了吗？(2) Can he be at home now?他现在能在家吗？注：以上三种句式中情态动词的语气按程度都是依次递减的。
Might, could并非的过may, can 去式，而表示语气较为委婉或可能性较小。
(二)情态动词表推测的三种时丄1.对将来情况的推测，用丨“情态动词+动词原形”。
(1) She must / may / might / could arrive before 5. 5:00前她一定/可能/也许到。
(2) She must/may/might/could walk miles and miles among the hills without meeting anyone・她一定/ 可能/也许会在山里一连走好几英里而遇不到一个人。
(1)He must / may / might / could be listening to the radio now.他一定/可能/也许正在听收音机。
(2)He can't ( couldn 't ) / may ( might ) not be at home at this time.这个时候他不可能/可能不在家。
(3)Mr. Bush is on time for everything . How can ( could ) he be late for the opening ceremony 布什先生一向准时，这次开幕式他怎么可能迟到呢？3•对过去情况的推测，用丨“情态动词+ have +过去分词”丨。
(1)It must / may / might / could have rained last night .The ground is wet.地湿了，昨晚肯定/可能/也许下雨了。
(2)The door was locked. He can ( could ) not / may ( might ) not have been at home .门锁着，他不可能/可能不在家。
(3)Can / Could he have gotten the book ?难道他找到书了吗？注：情态动词should / ought to 表推测时，意为"想必会，理应”但与"have +过去分词”连用时，则又可构成虚拟语气意为“本应该做某事却没做”。
例如：(4)It 's seven o 'clock. Jack should/ought to be here at any moment.现在七点钟了，杰克理应随时到达。
(推测)(5)She should / ought to have attended your birthday party, but she had to look after hermot her in hosp it al. (虚拟)她本该出席你的生日晚会的，可是她得在医院照顾她妈妈。
(6)Tom should not /ought not to have told me your secret, but he meant no harm. (虚拟)汤姆本不该告诉我你的秘密，可是他并无恶意。
(三)几组表推测的情态动词用法情态动词+完成时”是历年高考的热点，在做此类练习时，既需要掌握这一结构的基本用法，又应该仔细体会题干所提供的语言信息，准确理解语言环境和说话人的含义，尤其要注意题干中时态给予的暗示。
1. must have done表示对已经发生的事情的推测，意为一定，想必”，句子中表示的是一-种肯定的推测。
这种结构一般只用于肯定句，其否定形式是can，t (couldn ')thave done,表示不可能，肯定不会”。
例如：He didn ' t hear the phone ・ He must have been asleep・他没有听到电话响，他肯定是已经睡着了。
He must have bee n to Shan ghai・他一定去过上海。
They can 't have gone out , because the light is on .他们不可能出去，因为灯亮着。
2. can (could) have done表示对过去的时间内可能发生的事情的猜测，can have done —般只用于否定句和疑问句。
could have done还可以用于肯定句，常用来表示本来可能完成而实际未完成的动作。
例如：He can 't have finished the work so soon.这项工作他不可能完成得这样快。
We could have walked to the station , it was so near .我们本来是可以走到车站去的，路很近。
3. may ( might ) have done(1)表示对已经发生的事情的不太肯定的推测，意为“可能已经，或许已经”。
(2)虚拟用法表示本可以做，但却没做(表示很委屈地责备)If we had taken the other road , we might have arrived earlier.如果我们选择另一条路,我们可能会到得早一些。
He might have given you more help, he was very busy.他本来是可以给你更多帮助的，尽管他很忙。
4. needn 't have don指实际上做了本来不必要做的事，意为本来不必”例如：There was plenty of time . She needn 't have hurried.时间很充裕，她本不必匆忙。
You needn 't have told him the news.他本来不必把这个消息告诉他。
5. should (ought to ) have done指本该做而实际未做的事，意为“本来应该”。
其否定式(oughtn shouldn *t ')thave done则表示某种行为不该发生但却发生了。
例如：You should have started earlier , but you didn ' t.你本应该早一点出发，但是你没有。
You ought to have helped him (but you didn ) '. t 你本应该帮助他。
We shouldn 't have waited for her because she never came.我们本不应该等她，因为她根本不会来。
6. Would have done本想做(却没做)wouldn 't have done本不想做(却做了)I would have helped you, but I was too busy.我本想帮你，但我太忙了I stayed at a hotel in New York.——Oh, did you ? You ___ with Barbara.A. could have stayedB. could stayC. would say 2 Why didn ' t you tell me there was no meeting today ? I all tahye hwere through the heavy snow.4 A : Is John coming by train ?B: He should, but he ______ not. He likes driving his car.A. mustB. canC. needD. may5. Mr. White _____ a t 8:30 for the meeting, but he didn ' t show up.A. should have arrivedB. should arriveC. should have had arrivedD. should be arriving6. Sorry, I 'm late ・_I_h_a_ve turned off the alarm and gone to sleep again.A. mightB. shouldC. canD. will7. You _____ be tired — You've only been working for an hour ・A. must notB. won ' tC. can ' t D ・ may not8. —— I didn ' t go torkwyoesterday afternoon because my car broke down.1. D. must have stayedA. needn ' t have drivenB. can ' t have drivenC. mustn ' t have drivenD. shouldn ' t have driven3. I was really anxious about you. You home without a word.A. mustn ' t leave C. couldn ' t have leftB. shouldn ' t have leftD. needn ' t leaveYou mine. I wasn t using it.A. might borrowB. could have borrowedC. can have borrowed 9. ——A man answered the phone.D. ought to borrowI suppose it was her husband.A. mustn r t beB. couldn !t have beenC. may not have been ——It her husband.D. mustn 't have beenHe has been dead for ages.1) 1. 选择填空I didn ，t see A. mustn't C. needn't 2. One ought her in have spoken have spoken for what one has J nt done.the meeting room this morning ・ She at the meeting. B. shouldn ，t have spoken D. couldn ，t have spokenA. not to be punishedB. to not be punishedC. to not punished D ・ not be punished 3. If you really want yourself to be in good health, you must ________ always ____A. not; be smokingB. not; have smokedC. not; to smoke D ・ be not: smoking 4. With so much work on hand, you _______ t o see the game last night ・ mustn't go B. shouldn't go C. couldn ，t have goneD. shouldn ，t have gone 5. MostA. of the students felt rather disappointed at the English party ・ They say that it organized ・A. had beenB. had to beC. must have beenD. could have beenbetter 6. I'm surprised that he _ in the exam ・A. should failB. would have failedC. may have failedD. should have failed 7. The little girl there alone.A. not dare goB. dares not goC. dare 8. "Must we do it now?” N “ A. won ' t B. needn't 9. He said he would rather not A. doing B. to do C. do 10. You ____ to the meeting this afternoon if you havesomething important to do.A. needn't to comeB. don't need comeC. don't need comingD. needn't come11.Put on more clothes ・ You _ be feeling cold with only a shirt on. A. can B. could C. would D. mustnot go D. dare not to go o , youC. can ，t it right now.D. don't D. to be doingA. mayB. might C ・ could D. must 14. There was plenty of times ・ She _・A. mustn ，t have hurriedB. couldn ，t have hurriedC. must not hurryD. needn't have hurried 15. The plant is dead ・ I _it more water ・12. I ___ p lay football than basebal1.A. would ratherB. had betterC. like betterD. prefer 13. I thought you _ like something to read, so I have brought you some books.16. Youreturn the book now. You can keep it till next week if you like.C. mustn' t waitD. needn' t wait20. — May I stop here? — No, you _______ .A. mustn'tB. might notC. need n'tD. won 421. Ifs a fine day. Let 1 s go fishi ng, ___ ・A. won ' tweB. will weC. don 4 weD. shall we22. I didn*t see her in the meeting room this morning. She _____ at the meeting.A. mustn't have spoke nB. should n't have spokenC. needn't have spokenD. couldn't have spoken23. — Please don 4 make a noise.— ____ . I ' llbe as quiet as a mouse.A. Yes, I won'tB. No, I won'tC. No, I willD. Yes, I will24. The young man has made so much noise that he _____ not have been allowed to attend the concert.A. couldB. mustC. wouldD. should25. — Where is John? — He ________ in the library.A. should beB. must beC. can beD. must have been26. Since the road is wet this morning, ____ last night.A. it must rainB. it must be rainingC. it must have rainedD. it must have been rain 27. — Will your brother stay home tonight?— I ' m not quite sure. He _____ to the cinema tonight.D. can't have doneA. can'tB. mustn't 17. Ifs still early, you _____ . A. must n't hurry B. would n 't hurry 18. Please open the window, ___ ? A. can't you B. aren 11 you 19 WeC. needn'tD. may not C. may not hurry D. don't have to hurryC. do youD. will you for her because she never came. A. must n't have waited B. should n't have waitedA. must goB. can go 28. She*s already two hours late. What A. can have happenedC. should have happened 29. You must be a writer, ____ ?A. mustn't youB. are you 30. I got up early that morning, but I _ A. mustn't have doneC. needn't have doneC. may goD. may be going ___ toher?B. may have happened D. must happenC. must youD. are n't you so because I had no work to do. B. didn't need to do31. He _____ haveA. could32 I missed theA. must33. He ought toA. oughtn't34. Everyone ___ come here yesterday,B・ shouldlast bus, so I go home on foot.B・ have to win the firstprize, he?B・ shouldn，tdo his best for the but he did' tn.C. ought toC. mayC. mustn，tmodernizationsD. all the aboveD. had toD. both A and Bofour country.A. canB. may35. Let's clean our classroom,C. shouldD. mighttomorrow.A. mustB. may C ・ shall D. both B and C38. “Your phone number again? I _quite catch i” t. “It ' s 9568442.A. didn ' tB. couldn ，tC. don tD. can" t39. Mother _____ u s stories when we were children.A. was used to tellB. is used to tellingC. used to tellD. used to telling40. She would rather _____ more money on books ________ on clothes.A. cost …notB. to spare …don'tC. pay •••tha nD. spe nd •••tha n1. You ____ return the book now. You can keep it till next week if you like.4. I didn ，thear the phone ・ I _ asleep ・A. must beB. must have beenC. should beD. should have been5. If my lawyer _ here last Saturday, he _ me from going.A. had been; would have preventedB. had been; would preventC. were; would preventD. were; would have prevented6. He ____ you more help, even though he was very busy ・A. might have givenB. might have C ・ may have given D ・ may give7. If it _ for the snow, we _______ the mountain yesterday.A. were not; could have climbedB. were not; could climbC. had not been; could have climbedD. had not been; could climb8. Without electricity human life quite difficult today.A. isB. will be C ・ would have been D. would be9. A computer _____ think for itself, it must be told what to do.A. can tB. couldn'tC. may notD. might not10. Jenny ____ have kept her word ・ I wonder why she changed her mind ・A. mustB. shouldC. needD. would11. We _____ last night, but we went to the concert instead.A. must have studied B ・ might study C ・ should have studied D ・ would study12— Could I borrow your dictionary?—Yes, of course you _______ ・A. mightB. willC. canD. should13. Tom ought not to ____ me your secret, but he meant no harm ・A. have told B ・ tell C ・ be telling D ・ having toldA. will youB. don" t weC. shall weD. do you 36. Let us play A. will you basketball, _?B. don ，t weC. shall weD. do you 37. He asked me for this book many times. Please tell him that he have itA. can'tB. mustn't 2. Where is my pen? I ____ it.A. might loseB. would have lost3. I wish I _____ you yesterday. A. seen B. did seeC. needn'tD. may notC. should have lostD. must have lostC. had seenD. were to see14. 一If he ____ , he _____ that food・—Luckily he was sent to the hospital immediately.A. was warned; would not takeB. had been warned; would not have takenC. would be warned; had not takenD. would have been warned; had not taken15. Peter ____ come with us tonight, but he is" ntvery sure yet.A. mustB. mayC. canD. will16. I told Sally how to get here, but perhaps I for her ・A. had to write it outB. must have written it outC. should have written it out D ・ ought to write it out17. I didn't see your sister at the meeting. If she , she would have met my brother ・B. has brokenC. were brokenD. had been broken20. It's nearly seven o' clock ・ Jack be here at any momentA. mustB. needC. shouldD. can21 ・ 一 There were already five people in the car but they managed to take me as well.一 It ____ a comfortable journey ・A. can't be B ・ shouldn ，t be C ・ mustn ，t have been D. couldn ，t have been22. Johnny, you ____ p lay with the knife, you _hurt yourself.A. won 't; can ，tB. mustn't; mayC. shouldn 't; mustD. can't; shouldn ，t23. The fire spread through the hotel very quickly but everyone get out ・A. had toB. would C ・ could D ・ was able to24. 一 When can I come for the photos? I need them tomorrow afternoon. 一 They be ready by12:00.A. canB. shouldC. mightD. need25. 一 I stayed at a hotel while in New York ・一 Oh, did you? You _______ with Barbara ・A. could have stayed B ・ could stay C ・ would stay D ・ must have stayed26. — Will you stay for lunch?一 Sorry, _ ・ My brother is coming to see me.A. I mustn ' tB. I can ，tC. I needn'tD. I won ' t27. — Are you coming to Jeff's party?一 I'm not sure ・ I _go to the concert instead ・A. mustB. would C ・ should D ・ might28. 一 Write to me when you get home ・A. I mustB. I shouldC. I willD. I can29. I was really anxious about you, you home without a word ・A. mustn ' t leave B ・ shouldn't have left C ・ couldn ，t have left D ・ needn't leave30. — Is John coming by train?一 He should, but he ______ not ・ He likes driving his car ・A. mustB. canC. needD. mayA. has come 18. — Shall I 一 No, you A. needn'tB. did come C ・ came tell John about _ ・ I've told B. wouldn ' t D. had come19. When a pencil is partly in it? him already. C. mustn ，t aglass of water, it D. shouldn ，tlooks as if itA. breaks。