情态动词用法+have-done

ModalVerbsLet’sLearncancouldbeabletomaymightmustshall shouldwill wouldoughtto dareneedhavetousedtohadbetter常用的情态动词：情态动词＋havedonecan/could/may/mighthavedone(1)都表示对过去所发生的事情的推测。意为“也许／可能已经”。肯定句:may/might/couldhavedone(≠canhavedone)否定句:can’t/couldn’t/maynot/mightnothavedone疑问句:Can/Could/Might…havedone?(≠May…havedone?)

—She’stwohourslate—whatcan/couldhavehappened?Can/Couldhehavemissedhertrain?—Yes,shemay/mighthave.Shemay/might/couldhaveoversleptandgotuptoolate.MightIhavelostitsomewhere?

Compare:

Hecan’t/couldn’t/maynot/mightnothavegoneoutbecausethelight’son.

(现在对过去的推测)Ithoughthecouldn’t/mightnothavegoneoutbecausethelightwason.

(过去对过去之前的推测)Ithoughtitmightrain.(Itmayrain.)Iaskedifitcouldrain.(Canitrain?)

(过去对过去将来的推测)

Mywife’sinhospital—ourbabycould/may/mightarriveatanytime.

(现在对将来的推测)—Whatdoyouthinkthatnoisewas?—Itmay/might/couldhavebeenacat.(现在对过去的推测)—Whatdoyouthinkthatnoiseis?—Itmay/might/couldbeacat.(≠can)(现在对现在的推测)(2)could/mighthavedone还表示过去本能够／本可以做某事是而实际没有做，有时含有“责备”之意。

Inmyview,theaccidentcould/mighthavebeenprevented.Youcould/mighthavetoldmeaboutitearlier.(3)could/mighthavedone还表示过去本会发生某事而幸好没有发生。Youwerestupidtotryclimbingupthere.Youcould/mighthavekilledyourself.Youshouldn’thaverunacrosstheroadwithoutlookinground.Youmight/couldhavebeenknockeddownbyacar.(4)could/mighthavedone还用于虚拟语气中。表示“过去本会做某事”而没有做。

Ifhehadnotbeenbusythen,hecould/might(也可用would)havehelpedme.=Hecould/might/wouldhavehelpedme,buthewasbusythen.=Hewasbusythen.Otherwise/Or/Orelsehecould/might/wouldhavehelpedme.Hecould/might/wouldhavehelpedme,evenifhewasbusy.Icould/might/wouldnothavefinisheditintimewithoutyourhelp.2.musthavedone

表示对过去所发生的事情的肯定推测,意为“肯定／一定做了或发生了某事”。只用于肯定句中。

Someonemusthaveopenedthecage—thelioncouldn’thaveescapedonitsown.Ididn’thearthephone.Imusthavebeenasleep.

Compare:—Wasthatthemanagerwhowalkedby?—Itmusthavebeen./No,itcan’thavebeen.—Isthatthepostmanwhoisknockingatthedoor?—Itmustbe./Itcan’tbe.

3.should/oughttohavedone表示过去本应该做某事而实际上没有做，含有“责备”之意。Theplant’sdead.MaybeIshouldhavegivenitmorewater.IknowIoughtnottohavetakenthemoney.Compare:

Compare:Wedidn’texercisemuch,butwereallyoughttohave/shouldhave.Wedon’texercisemuch,butwereallyoughtto/should.(2)表示对过去所发生的事情的推测,意为“应该会”，“理应会”。

It’seighto’clock.Heshouldhavearrivedhere(shouldbehere)bynow.

Thatwasdisappointing—weshouldhavewonthatgameeasily.(3)有时表示对将来要发生的事情的推测。

IshouldhavefinishedreadingitbyFriday.4.needn’thavedone

表示过去本不需要做某事而实际上做了。

Therewasplentyoftime.Ineedn’thavehurried.(ButIhurried.)Compare:Therewasplentyoftime,soIdidn’tneedtohurry.(SoIdidn’thurry.)Compare:There’splentyoftime,soIneedn’thurry.(now)1.SorryI'mlate.I_____haveturnedoffthealarmclockandgonebacktosleepagain.A.mightB.should

C.canD.will2.Peter_____comewithustonight,butheisn’tverysureyet.

A.mustB.mayC.canD.will3.Somepeoplewhodon’tliketotalkmucharenotnecessarilyshy,they

justbequietpeople.A.mustB.mayC.shouldD.would4.Liza___wellnotwanttogoonthetrip---shehatestraveling.（2008全国II）

A.will

B.can

C.must

D.may

ABBD5.Michael____beapoliceman,forhe’smuchtooshort.A.needn’tB.can’tC.shouldD.may6.----IstayedatahotelwhileinNewYork.----Oh,didyou?You____withBarbara.A.couldhavestayedB.couldstayC.wouldstayD.musthavestayed7