1、Why is the road Why is the road so wet?so wet?It It must have rainedmust have rainedlast night.last night.must have done对过去的非常肯定的推测（语气最强）对已发生的过去情况的推测，若陈述句谓语部分有“must have done”，而且有表示过去的时间状语,问句部分用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
2、去情况的推测，若陈述句谓语部分有“must have done”，若没有表示过去的时间状语，问句部分用havent 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，若陈述句谓语部分有“must have done”，若没有表示过去的时间状语，问句部分用havent 或hasnt.这个房间昨天肯定被清扫了。The room _ _ _ _ yesterday.must have been cleaned他一定已经背了5000单词了。He _ _ _ 5,000 words.must have learntYou
3、 must have seen the film“Journey to the West”,_ _?havent youThey must have been to the World Expo last week,_ _?didnt theyA:Where are the girls?Could they have gone home?B:No,they cant have gone home.Its so early.can have done对过去的疑问推测cant have done对过去的否定推测疑问句和否定句-Where is John?Can he have gone to th
4、e playground?-No,he cant have gone to the playground It is raining.-_Mr King _the letter?金先生已经收到那封信了吗？-No,he _it.不，他不可能收到。Canhave receivedcant have received-Look,the lights are off in their room.-Where have they gone?-They might have gone to the cinema.may/might have done某事有可能发生过(表示对过去的不太肯定的推测，语气比mu
5、st have done 弱)用于肯定句和否定句(may的语气比might稍强)-Where did Adam get that new football?He hasnt got any money.-It _ a present.After all,it was his birthday last week.A.might have been B.might beHe _out because the light was on.A.may not have gone B.may have not goneC.may not go D.must not have goneA:Here is
6、a doll for your daughter.B:Thank you so much.Its beautiful.But you neednt have bought it.You have bought so many for her.neednt have done本没有必要做某事（但此事已做）We _the plant because it rained last night.(本无必要)neednt have wateredOh,Im not feeling well in the stomach.I shouldnt have eaten so much fried chicke
7、n just now.shouldnt have done本不该做某事（但此事已做）表示责备He should have repaired the bike yesterday.should have done本应该做某事（但此事未做）表示责备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。You _ _ _to me.shouldnt have liedcould+have done“本能够，本可以做某事”但却没做他本能够按时完成这项任务的。He _the task on time,but he
8、didnt do it.could have finishedFinding the ruleModal verbs+have doneExplanationsExample sentencesmust have doneBelieving what happened in the past is the case(used only in positive sentences)It must haverained last night.can/could have done-Where is John?Could he have gone to the playground?-No,he c
9、ant have 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 done.Suggesting that it is possible that something happened or was true(used only in positive/negative sentences)
10、They might have mistaken youshould/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 doneindicating that it is not necessary for sb.to do sth,though he/she did it.You neednt have watered the
11、plant.It rained last night.高考例析1.Sorry Im late.I _ have turned off the alarm clock and gone back to sleep again.（2000 北京春季）A.might B.should C.can D.will答案为 A。表推测的用法。句意：对不起,我迟到了。我(当时)兴许是关了闹钟又回去睡觉了。might 相当于may,但语气更加不肯定。2.I was really anxious about you.You_ home without a word.(01 全国)A.mustnt leave B.
12、shouldnt have left C.couldnt have left D.neednt leave答案为 B。虚拟语气用法。句意：我（那时）真地很担心你。你本不应该不留个话就离开家。3.Ill tell Mary about her new job tomorrow.You_ her last week.（04 福建）A.ought to tell B.would have told C.must tell D.should have told答案为 D。虚拟语气用法。句意：-我明天要告诉她我的新工作的情况。-你本应该上周告诉她。4.Tom graduated from college
13、 at a very young age.Oh,he _ have been a very smart boy then.（04 全国IV）A.could B.should C.might D.must答案为 D。表推测的用法。句意：汤姆很年轻的时候就大学毕业了。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)A.should B.must C.wouldnt D.cant答案为 B。用法同4题。句意：他肯定做完了工作，不
14、然他就不会在海边痛快地玩儿了。6.Do you know where David is?I couldnt find him anywhere.Well.He _ have gone farhis coats still here.（05湖北卷）Ashouldnt Bmustnt Ccant Dwouldnt答案为 C。表推测的用法。句意：你知道大卫在哪儿吗？我哪儿也找不到他。瞧，他不可能走远他的上衣还在这儿呢。cant 相当与 couldnt，但后者语气更加委婉。练习1.The woman biologist stayed in Africa studying wild animals fo
15、r 13 years before she returned.Oh,dear!She _ a lot of difficulties!(05 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）A.must drop B.must have dropped C.must be dropping D.must have been dropped3.Mr.
16、White _ at 8:30 for the meeting,but he didnt show up.（04 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）A.could B.would C.must D.need5.Tom is never late for work.Why is he absent today?Something _ to him.
17、(05 江西卷)A.must happen B.should have happened C.could have happened D.must have happened6.I _ have been more than six years old when the accident happened.(05 天津卷)A.shouldnt B.couldnt C.mustnt D.needntChoose the best answer for each blank.1)I told him the news just now.Really?You _ him.He knew it alr
18、eady.A.shouldnt have told B.may have told C.neednt have told D.couldnt have told2)I cant find my pen anywhere.I _ it.Thats impossible.I saw you writing with it ten minutes ago.A.might lose B.would have lost C.should have lost D.must have lostCD3)That must be Jack.It cant be him.He _ within such a sh
19、ort time.He said he would call me as soon as he arrived.A.mustnt have arrived B.B.shouldnt have arrivedC.cant have arrived D.need not have arrived4)Where are Joan and Mary?I think they _ early.A.should have left B.must have left C.can have left D.neednt have leftCB5)Did you see that car nearly hit m
20、e?I _ killed.Yes.It was going so fast.Luckily you responded quickly.A.could have been B.may have been C.must have been D.wasB6)Mom,I swept the floor a moment ago.Thank you,son.But you _ it.Its not very dirty yet.A.should have swept B.neednt have sweptC.may have swept D.can have swept7)Its so dry the
21、se days.Even the plant is dead.Yes.You _ it more water.A.will give B.should have givenC.may send D.can have been sentBB8)John passed the exam,although he didnt study very much for it.The exam _ difficult.A.cant have been B.must have been C.couldnt be D.might have been9)I wonder why they are late.The
22、y _ the train.A.can miss B.may have missed C.could miss D.might missAB10)He _ to help us yesterday,but he didnt.You must forgive him.He was ill yesterday.A.should have come B.could have come C.must have come D.can have comeAFind and correct the mistake in each of the following sentences.1)She should
23、 had finished the work three days ago.2)You are wet through.You should have been caught in the rain.She should have finished the work three days ago.You are wet through.You must have been caught in the rain.3)I must have helped them,but I wasnt able to.4)You mustnt have seen the movie before,for it
24、was made last week.I should have helped him,but I wasnt able to.You cant have seen the movie before,for it was made last week5)All the lights were off at eleven last night.The students mustnt have been studying in the classroom until twelve.All the lights were off at eleven last night.The students c
25、ant have been studying in the classroom until twelve.Fill in each blank with the present perfect form of a model verb.1)Husband:I bought a new skirt for you.Wife:Thank you,dear.But you _ _ done that.Ive got so many.2)Mother:Who _ cooked the meal?Daughter:It must have been Father.Mother:It cant have
26、been your father.He told me he was going to Chengdu on business this morning.havecould/can haveneednt3)Policeman:You _ stopped at the red light.Why did you keep on driving?Driver:Im terribly sorry.I didnt see the light.4)Teacher:Everyone is listening carefully.Why did you look out of the window?Student:Im sorry.I _ done that.should haveshouldnt haveHomework Applying the rules
