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對過去的非?？隙ǖ耐茰y（語氣最強(qiáng)）對已發(fā)生的過去情況的推測，若陳述句謂語部分有“musthavedone”，而且有表示過去的時(shí)間狀語,問句部分用didn't；1)Theymusthavegonetherelastnight,

didn'tthey?2)Theymusthavearrivedbynow,haven’tthey?對已發(fā)生的過去情況的推測，若陳述句謂語部分有“musthavedone”，若沒有表示過去的時(shí)間狀語，問句部分用haven’t或hasn’t.3)HemusthavebeentotheGreatWall,hasn'the?對已發(fā)生的過去情況的推測，若陳述句謂語部分有“musthavedone”，若沒有表示過去的時(shí)間狀語，問句部分用haven’t或hasn’t.這個(gè)房間昨天肯定被清掃了。Theroom_____________________yesterday.

musthavebeencleaned他一定已經(jīng)背了5000單詞了。He_____________5,000words.musthavelearntYoumusthaveseenthefilm“JourneytotheWest”,___________?

haven’tyouTheymusthavebeentotheWorldExpolastweek,_________?didn’tthey

canhavedone對過去的疑問推測

can’thavedone對過去的否定推測疑問句和否定句--WhereisJohn?Canhehavegonetotheplayground?--No,hecan’thavegonetotheplaygroundItisraining.--____MrKing_____________theletter?金先生已經(jīng)收到那封信了嗎？--No,he__________________it.不，他不可能收到。Canhavereceivedcan’thavereceivedmay/mighthavedone某事有可能發(fā)生過(表示對過去的不太肯定的推測，語氣比musthavedone弱)用于肯定句和否定句(may的語氣比might稍強(qiáng))---WheredidAdamgetthatnewfootball?Hehasn’tgotanymoney.---It____apresent.Afterall,itwashisbirthdaylastweek.A.mighthavebeenB.mightbeHe______outbecausethelightwason.A.maynothavegone

B.mayhavenotgoneC.maynotgoD.mustnothavegoneneedn’thavedone本沒有必要做某事（但此事已做）We___________________theplantbecauseitrainedlastnight.(本無必要)needn’thavewateredshouldn’thavedone本不該做某事（但此事已做）表示責(zé)備Heshouldhaverepairedthebikeyesterday.shouldhavedone本應(yīng)該做某事（但此事未做）表示責(zé)備Oh,I'm

not

feeling

well

in

the

stomach.I

shouldn’thaveeatensomuchfriedchickenjustnow.你本應(yīng)該先完成你的作業(yè)。You________________yourhomeworkfirst.shouldhavefinished你本不應(yīng)該跟我撒謊。You________________tome.shouldn’thavelied高考例析1.SorryI’mlate.I_____haveturnedoffthealarmclockandgonebacktosleepagain.（2000北京春季）

A.mightB.shouldC.canD.will答案為A。表推測的用法。句意：對不起,我遲到了。我(當(dāng)時(shí))興許是關(guān)了鬧鐘又回去睡覺了。might相當(dāng)于may,但語氣更加不肯定。2.Iwasreallyanxiousaboutyou.You____homewithoutaword.(01全國)

A.mustn'tleave

B.shouldn'thaveleft

C.couldn'thaveleft

D.needn'tleave答案為B。虛擬語氣用法。句意：我（那時(shí)）真地很擔(dān)心你。你本不應(yīng)該不留個(gè)話就離開家。3.—I’lltellMaryabouthernewjobtomorrow.

—You__herlastweek.（04福建）

A.oughttotell

B.wouldhavetold

C.musttell

D.shouldhavetold答案為D。虛擬語氣用法。句意：---我明天要告訴她我的新工作的情況。---你本應(yīng)該上周告訴她。4.—Tomgraduatedfromcollegeataveryyoungage.

—Oh,he____havebeenaverysmartboythen.（04全國IV）

A.could

B.should

C.might

D.must答案為D。表推測的用法。句意：——湯姆很年輕的時(shí)候就大學(xué)畢業(yè)了?！?，他肯定是一個(gè)很聰明的男孩兒。5.He_____havecompletedhiswork;otherwise,hewouldn'tbeenjoyinghimselfbytheseaside.(05北京卷)

A.should

B.must

C.wouldn't

D.can't答案為B。用法同4題。句意：他肯定做完了工作，不然他就不會(huì)在海邊痛快地玩兒了。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答案為C。表推測的用法。句意：—你知道大衛(wèi)在哪兒嗎？我哪兒也找不到他。—瞧，他不可能走遠(yuǎn)—他的上衣還在這兒呢。can't相當(dāng)與couldn't，但后者語氣更加委婉。練習(xí)—ThewomanbiologiststayedinAfricastudyingwildanimalsfor13yearsbeforeshereturned.

—Oh,dear!She___alotofdifficulties!(05江蘇卷)

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廣西）

A.shouldhavearrived

B.shouldarrive

C.shouldhavehadarrived

D.shouldbearriving

4.Hepaidforaseat,whenhe___haveenteredfree.（05山東卷）

A.could

B.would

C.must

D.need5.—Tomisneverlateforwork.Whyisheabsenttoday