语法专练之情态动词

I.can/could•表否定的猜测can’t/couldn’tdo现在或将来不可能…e.g.Hecan’t/couldn’tbeherfather;he’stooyoung.can’t/couldn’tbedoing现在不可能正在…e.g.Hecan’t/couldn’tbewaitingforusatthestop.can’t/couldn’thavedone（过去）不可能…e.g.Ican’t/couldn’thavelostmykeys.Ineverdropthings.Shecan’thavecaughtthe9:10train,forsheonlyleftherhouseat9:15.比较：--MayIseethesecretary?--Try.Butshemaynotwanttoseeanyone.•can/could用在疑问句中表猜测e.g.Can/CoulditbeJohn?Couldthebankhavemadeamistake?e.g.Thispenlooksmine,yetitisn’t.Whosecan/coulditbe?（可能）会是谁的呢？Wherecanshehavegone?•couldhavedone过去能够做某事而没做e.g.Hewentonfoot,buthecouldhavetakenabus.e.g.Iwasfiveminuteslate,otherwiseIcouldhavecaughtthetrain.Practice:Icouldhavefinisheditbetter,butI_____noenoughtime.A.wouldhaveB.haveC.hadD.hadhadii.may/might•may/might表肯定的猜测（语气较弱）may/mightdo现在或未来可能发生e.g.—Whyisn’tJohninclass?—Idon’tknow.Hemay/mightbesick.—Whatareyougoingtodotonight?—Ihaven’tmadeupmymindyet.Imay/mightgotothelibraryorImay/mightjuststayathome.may/mightbedoing现在可能正在…e.g.Myfatherisnothere.Hemay/mightbeworkinginthegarden.将来可能会…e.g.Theymay/mightbewaitingatthestationwhenwearrive.may/mighthavedone过去可能发生e.g.Helooksunhappy.Hemay/mighthavefailedintheexamination.•mighthavedone过去可能发生某事但未发生e.g.Youwerestupidtotryclimbingupthere.Youmighthavekilledyourself.e.g.Itisagoodthingyoudidn’tlendhimthemoney.Youmightneverhavegotitback.•may用于目的/让步状语从句中，表示可以或可能e.g.Weworkhardthatwemayliveincomfort.e.g.Whatevermayhappen(=Whateverhappens),itdoesn’tconcernus.iii.must•must表肯定的猜测mustdo现在一定会e.g.Hemustknowherphonenumber.Hehashadnosleepfor48hours.Hemustbeexhausted.mustbedong现在一定正在或即将发生e.g.Itmustberainingnow.Hemustbearrivingtonight.musthavedone猜测(过去)一定已经发生e.g.Theymusthaveleft,fornobodyisin.Youwereontime.Youmusthavegotupearlythatmorning.musthavebeendoing当时一定正在e.g.Marywasn’tathomewhenwewenttovisither.Shemusthavebeenstudyingatthelibrary.Notice:反意疑问句•Hemustberich,•Youmusthavehisnumber,•Theyarenotadmittedtothecinema.Hemusthavelosttheirtickets,•TheymusthavemetJohnonthewayhomeyesterday,•Iknockedatthedoor,butnobodyanswered.Hemusthavebeenasleep,•Atthatmoment,nooneansweredmyphone.Theymusthavebeenreadinginthestudy,isn’the?don’tyou?hasn’the?didn’tthey?wasn’the?weren’tthey?•must表主语的固执；偏要…e.g.Hemustalwayshavehisownway.e.g.Whymustyoubesostubborn?e.g.AsIwassittingdowntosupper,thetelephonemustring.iv.shall/should/oughtto•should表虚拟shouldhavedone/oughttohavedone过去应该做某事而没做shouldn’thavedone/oughtn’ttohavedone过去不应该做某事但做了e.g.Youfailedagain.Youshouldhavereviewedyourlessons.(Butyoudidn’t.)e.g.Theplantdied.Heoughtn’ttohavegivenittoomuchwater.(Buthedid.)•should表猜测：按照常理或常态认为应该如何e.g.Inmyopinion,sheshouldbeelectedbecausesheishonest,knowledgeable,andcompetent.•should表万一，用于条件状语从句中e.g.Ifyoushouldhaveanydifficultywithit,ringthisnumber.=Shouldyouhaveanydifficultywithit,ringthisnumber.•shall用于第一、第三人称，表建议或征求意见，意为“……好吗？”，“要不要……?”e.g.Shallwegotothemovies?Shallhestayhereorleavenow?•shall用于第二、第三人称，表示说话者的警告、命令、恐吓、允诺、规定等e.g.Personsunder18shallnotbeemployedinnightwork．Youshallgetout.v.will/would•will表物的属性；人或动物的习性e.g.Woodwillfloat.e.g.Thedoorwillnotopen.e.g.Unlessdrivenbyhunger,alionwillnotattackman.e.g.Adrowningmanwillcatchatastraw.•would(表示过去习惯、行为、习俗)老是,总是e.g.Wheneverhehadtime,hewoulddosomereading.（过去）他一有时间，就会读点书。vi.dare•做为情态动词:不用于肯定句•现在时I/Hedarenothaveatry.Darehehaveatry?•过去时I/Hedarednothaveatry.Daredhehaveatry?•做为普通动词•现在时Idaretohaveatry./Hedarestohaveatry.Idon’t/Hedoesn’tdare(to)haveatry.Doyou/Doeshedare(to)haveatry?•过去时I/Hedaredtohaveatry.I/Hedidn’tdare(to)haveatry.Didyou/Didhedare(to)haveatry?vii.need•needn’thavedone做了过去不必做的事e.g.Oh,therewasplentyoftime.Youneedn’thavehurried.Practice:SinceitwasSundayyesterday,I_____towork;soIwentfishing.A.needn’thavegoneB.oughtn’tgoC.mustn’havegoneD.didn’tneedtogo