情态动词完成时的推测

Whyistheroadsowet?Itmusthaverained

lastnight.A:Wherearethegirls?

Cantheyhavegonehome?B:No,theycan’thavegonehome.It’ssoearly.--Look,thelightsareoffintheirroom.--Wherehavetheygone?--Theymighthavegonetothecinema.A:Hereisadollforyourdaughter.B:Thankyousomuch.It’sbeautiful.Butyouneedn’thaveboughtit.Shehassomanyathome.FindingtheruleBelievingwhathappenedinthepastisthecase(usedonlyinpositivesentences)indicatingthatsomethingwasapossibilityinthepast,thoughitdidnotactuallyhappen(negativeorinterrogativesentences)Suggestingthatitispossiblethatsomethinghappenedorwastrue(usedonlyinpositive/negativesentences)indicatingthatsomethingdidnot/didhappen,butthespeakerwishesithad(not)happened.indicatingthatitisnotnecessaryforsb.todosth,thoughhe/shedidit.

musthavedone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“musthavedone”，而且有表示过去的时间状语,问句部分用didn't；1)Theymusthavegonetherelastnight,

didn'tthey?2)Theymusthavearrivedbynow,haven’tthey?对已发生的过去情况的推测，若陈述句谓语部分有“musthavedone”，若没有表示过去的时间状语，问句部分用haven’t或hasn’t.3)HemusthavebeentotheGreatWall,hasn'the?对已发生的过去情况的推测，若陈述句谓语部分有“musthavedone”，若没有表示过去的时间状语，问句部分用haven’t或hasn’t.这个房间昨天肯定被清扫了。Theroom_____________________yesterday.

musthavebeencleaned他一定已经背了5000单词了。He_____________5,000words.musthavelearntYoumusthaveseenthefilm“JourneytotheWest”,___________?

haven’tyouTheymusthavebeentotheWorldExpolastweek,_________?didn’tthey

canhavedone对过去的疑问推测

can’thavedone对过去的否定推测疑问句和否定句--WhereisJohn?Canhehavegonetotheplayground?--No,hecan’thavegonetotheplaygroundItisraining.--____MrKing_____________theletter?金先生已经收到那封信了吗？--No,he__________________it.不，他不可能收到。Canhavereceivedcan’thavereceivedmay/mighthavedone某事有可能发生过(表示对过去的不太肯定的推测，语气比musthavedone弱)用于肯定句和否定句(may的语气比might稍强)---WheredidAdamgetthatnewfootball?Hehasn’tgotanymoney.---It____apresent.Afterall,itwashisbirthdaylastweek.A.mighthavebeenB.mightbeHe______outbecausethelightwason.A.maynothavegone

B.mayhavenotgoneC.maynotgoD.mustnothavegoneneedn’thavedone本没有必要做某事（但此事已做）We___________________theplantbecauseitrainedlastnight.(本无必要)needn’thavewateredshouldn’thavedone本不该做某事（但此事已做）表示责备Heshouldhaverepairedthebikeyesterday.shouldhavedone本应该做某事（但此事未做）表示责备Oh,I'm

not

feeling

well

in

the

stomach.I

shouldn’thaveeatensomuchfriedchickenjustnow.你本应该先完成你的作业。You________________yourhomeworkfirst.shouldhavefinished你本不应该跟我撒谎。You________________tome.shouldn’thavelied高考例析1.SorryI’mlate.I_____haveturnedoffthealarmclockandgonebacktosleepagain.（2000北京春季）

A.mightB.shouldC.canD.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.Iwasreallyanxiousaboutyou.You____homewithoutaword.(01全国)

A.mustn'tleave

B.shouldn'thaveleft

C.couldn'thaveleft

D.needn'tleave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.—I’lltellMaryabouthernewjobtomorrow.

—You__herlastweek.（04福建）

A.oughttotell

B.wouldhavetold

C.musttell

D.shouldhavetold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.—Tomgraduatedfromcollegeataveryyoungage.

—Oh,he____havebeenaverysmartboythen.（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_____havecompletedhiswork;otherwise,hewouldn'tbeenjoyinghimselfbytheseaside.(05北京卷)

A.should

B.must

C.wouldn't

D.can't答案为B。用法同4题。句意：他肯定做完了工作，不然他就不会在海边痛快地玩儿了。6.—DoyouknowwhereDavidis?Icouldn’tfindhimanywhere.

—Well.He____havegonefar—hiscoat’sstillhere.（05湖北卷）A．shouldn't

B．mustn't

C．can't

D．wouldn't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。can't相当与couldn't，但后者语气更加委婉。练习—ThewomanbiologiststayedinAfricastudyingwildanimalsfor13yearsbeforeshereturned.

—Oh,dear!She___alotofdifficulties!(05江苏卷)

A.maygothrough

B.mightgothrough

C.oughttohavegonethrough

D.musthavegonethrough2.Ihavelostoneofmygloves.I_____itsomewhere.（05北京春季）

A.mustdrop

B.musthavedropped

C.mustbedropping

D.musthavebeendropped3.Mr.White___at8:30forthemeeting,buthedidn'tshowup.（04广西）

A.shouldhavearrived

B.shouldarrive

C.shouldhavehadarrived

D.shouldbearriving

4.Hepaidforaseat,whenhe___haveenteredfree.（05山东卷）

A.could

B.would

C.must

D.need5.—Tomisneverlateforwork.Whyisheabsenttoday