语法专练之情态动词

I.can/could,表否定的猜测cant/couldntdo现在或将来不可能e.g.Hecant/couldntbeherfather;hestooyoung.cant/couldntbedoing现在不可能正在e.g.Hecant/couldntbewaitingforusatthestop.,cant/couldnthavedone（过去）不可能e.g.Icant/couldnthavelostmykeys.Ineverdropthings.Shecanthavecaughtthe9:10train,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,yetitisnt.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.wouldhaveB.haveC.hadD.hadhad,ii.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.WhyisntJohninclass?Idontknow.Hemay/mightbesick.Whatareyougoingtodotonight?Ihaventmadeupmymindyet.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.Itisagoodthingyoudidntlendhimthemoney.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),itdoesntconcernus.,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.Marywasntathomewhenwewenttovisither.Shemusthavebeenstudyingatthelibrary.,Notice:反意疑问句Hemustberich,Youmusthavehisnumber,Theyarenotadmittedtothecinema.Hemusthavelosttheirtickets,TheymusthavemetJohnonthewayhomeyesterday,Iknockedatthedoor,butnobodyanswered.Hemusthavebeenasleep,Atthatmoment,nooneansweredmyphone.Theymusthavebeenreadinginthestudy,isnthe?,dontyou?,hasnthe?,didntthey?,wasnthe?,werentthey?,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shouldnthavedone/oughtnttohavedone过去不应该做某事但做了e.g.Youfailedagain.Youshouldhavereviewedyourlessons.(Butyoudidnt.)e.g.Theplantdied.Heoughtnttohavegivenittoomuchwater.(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.Personsunder18shallnotbeemployedinnightworkYoushallgetout.,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.Idont/Hedoesntdare(to)haveatry.Doyou/Doeshedare(to)haveatry?过去时I/Hedaredtohaveatry.I/Hedidntdare(to)haveatry.Didyou/Didhedare(to)haveatry?,vii.need,n