情态动词完成时的推测

1、 A: Where are the girls? Can they have gone home?B: No, they cant have gone home. Its so early.-Look, the lights are off in their room.-Where have they gone?-They might have gone to the cinema.A: Here is a doll for your daughter.B: Thank you so much. Its beautiful. But you neednt have bought it. She

2、 has so many at home.Finding the ruleModal verbs + have doneExplanationsExample sentencesmust have doneIt must have rained last night.Believing what happened in the past is the case (used only in positive sentences)can/could have done -Where is John? Can he have gone to the playground?-No, he cant h

3、ave gone to the playground. It is raining.indicating that something was a possibility in the past , though it did not actually happen (negative or interrogative sentences)may/might have doneThey might have mistaken you.Suggesting that it is possible that something happened or was true (used only in

4、positive/ negative sentences)should/shouldnt have doneYou should have done your homework first.indicating that something did not / did happen, but the speaker wishes it had (not) happened.neednt have doneYou neednt have watered the plant. It rained last night.indicating that it is not necessary for

5、sb. to do sth, though he / she did it. 对已发生的过去情况的推测，若陈述对已发生的过去情况的推测，若陈述句谓语部分有句谓语部分有“must have done”，而，而且且有表示过去的时间状语有表示过去的时间状语, 问句部分问句部分用用didnt； 1) They must have gone there last night, didnt they? 2)They must have arrived by now, havent they?对已发生的过去情况的推测，若陈述对已发生的过去情况的推测，若陈述句谓语部分有句谓语部分有“must have don

6、e”，若，若没有表示过去的时间状语，问句部分没有表示过去的时间状语，问句部分用用havent 或或hasnt .3) He must have been to the Great Wall,hasnt he? 对已发生的过去情况的推测，若陈述对已发生的过去情况的推测，若陈述句谓语部分有句谓语部分有“must have done”，若，若没有表示过去的时间状语没有表示过去的时间状语，问句部分，问句部分用用havent 或或hasnt .这个房间昨天肯定被清扫了。这个房间昨天肯定被清扫了。The room _ _ _ _ yesterday. must have been cleaned他一定已经

7、背了他一定已经背了5000单词了。单词了。He _ _ _ 5,000 words.must have learntYou must have seen the film “Journey to the West” , _ _? havent youThey must have been to the World Expo last week, _ _? didnt they-Where is John? Can he have gone to the playground?-No, he cant have gone to the playground It is raining.- _Mr

8、 King _the letter?金先生已经收到那封信了吗？金先生已经收到那封信了吗？-No, he _it.不，他不可能收到。不，他不可能收到。Canhave receivedcant have receivedmay/might have done某事有可能发生过某事有可能发生过(表示对过去的不太肯定的推测，表示对过去的不太肯定的推测，语气比语气比must have done 弱弱)-Where did Adam get that new football? He hasnt got any money. -It _ a present. After all, it was his bi

9、rthday last week. A. might have been B. might be He _out because the light was on.A. may not have gone B. may have not goneC. may not go D. must not have goneWe _the plant because it rained last night. (本无必要本无必要)neednt have wateredshouldnt have done本不该做某事本不该做某事（但此事已做）（但此事已做）He should have repaired t

10、he bike yesterday.should have done本应该做某事本应该做某事（但此事未做）（但此事未做）Oh, Im not feeling well in the stomach. I shouldnt have eaten so much fried chicken just now. 你本应该先完成你的作业。你本应该先完成你的作业。You _ _ _ your homework first. should have finished你本不应该跟我撒谎。你本不应该跟我撒谎。You _ _ _to me.shouldnt have lied高考例析高考例析 1. Sorry

11、Im late. I _ have turned off the alarm clock and gone back to sleep again. （2000 北京春季）北京春季）A. might B. should C. can D. will 答案为答案为 A。表推测的用法。句意：对。表推测的用法。句意：对不起不起, 我迟到了。我我迟到了。我(当时当时)兴许是关兴许是关了闹钟又回去睡觉了。了闹钟又回去睡觉了。might 相当于相当于 may, 但语气更加不肯定。但语气更加不肯定。2. I was really anxious about you. You_ home without a

12、word. (01 全国全国)A. mustnt leave B. shouldnt have left C. couldnt have left D. neednt leave 答案为答案为 B。虚拟语气用法。句意：我。虚拟语气用法。句意：我（那时）真地很担心你。你本不应该（那时）真地很担心你。你本不应该不留个话就离开家。不留个话就离开家。3. Ill tell Mary about her new job tomorrow. You_ her last week. （04 福建）福建）A. ought to tell B. would have told C. must tell D. s

13、hould have told答案为答案为 D。虚拟语气用法。句意：。虚拟语气用法。句意：-我明天要告诉她我的新工作的情我明天要告诉她我的新工作的情况。况。 -你本应该上周告诉她。你本应该上周告诉她。4. Tom graduated from college at a very young age. Oh, he _ have been a very smart boy then. （04 全国全国IV） A. could B. should C. might D. must答案为答案为 D。表推测的用法。句意：。表推测的用法。句意：汤姆很年轻的时候就大学毕业了。汤姆很年轻的时候就大学毕业了。

14、哦，他肯定是一个很聪明的男孩儿。哦，他肯定是一个很聪明的男孩儿。 5. He _ have completed his work; otherwise, he wouldnt be enjoying himself by the seaside. (05 北京卷北京卷) A. should B. must C. wouldnt D. cant答案为答案为 B。用法同。用法同4题。句意：他题。句意：他肯定做完了工作，不然他就不会肯定做完了工作，不然他就不会在海边痛快地玩儿了。在海边痛快地玩儿了。 6. Do you know where David is? I couldnt find him

15、anywhere. Well. He _ have gone farhis coats still here. （05湖北卷）湖北卷） Ashouldnt Bmustnt Ccant Dwouldnt答案为答案为 C。表推测的用法。句意：。表推测的用法。句意：你你知道大卫在哪儿吗？我哪儿也找不到知道大卫在哪儿吗？我哪儿也找不到他。他。瞧，他不可能走远瞧，他不可能走远他的上衣还他的上衣还在这儿呢。在这儿呢。cant 相当与相当与 couldnt，但，但后者语气更加委婉。后者语气更加委婉。 练习练习1. The woman biologist stayed in Africa studying w

16、ild animals for 13 years before she returned. Oh, dear! She _ a lot of difficulties! (05 江苏卷江苏卷) A. may go through B. might go throughC. ought to have gone through D. must have gone through2. I have lost one of my gloves. I _ it somewhere. （05 北京春季）北京春季）A. must drop B. must have dropped C. must be d

17、ropping D. must have been dropped 3. Mr. White _ at 8:30 for the meeting, but he didnt show up. （04 广西）广西） A. should have arrived B. should arriveC. should have had arrived D. should be arriving4. He paid for a seat, when he _ have entered free. （05 山东卷）山东卷）A. could B. would C. must D. need5. Tom is never late fo