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(能)(需要)FromJasmineKan情态动词后面+动词原形情态动词没有人称和数的变化Icannotplaybasketball.Ineedbuy/boughtacomputer.(需要)Shecan/cansrideahorse.Amyneed/needsbuyabook.否定式构成是在情态动词后面加notIcanplay/playedbasketball.用法:①表示能力:HecanspeakalittleEnglish.Canyoufly?③表示请求或允许:CanIhelpyou?②表示猜测:ThatcannotbeourEnglishteacher,becauseshehasgonetoShanghai.could也可表示请求，语气委婉，主要用于疑问句，不可用于肯定句，答语应用canCouldIcometoseeyoutomorrow?Yes,youcan.（否定答语可用No,I'mafraidnot.）用法:①表示请求或允许:MayIgohome，please?(1)以may（表许可或请求）开头的一般疑问句,肯定回答用may，否定回答用mustn't或can't.(2)在疑问句中不用于第二人称②表示可能性:Youmayberight.No,you_________(可以)Yes,youmay.might为may的过去式，但也可以代替may，语气较为婉转客气或更加不肯定。Youmightberight.mustn’t/youcan’t.试比较:●Youmaynotsmokehere．(不可以)语气轻●Youcan’tsmokehere．（不能）重●Youmustn’tsmokehere．（决不可）最重用法:既可以做情态动词,也可以做实意动词②实意动词(needtodosth):①情态动词(needdosth):Ineedbuyabighouse.(需要)Heneeddrivemehome.DoIneedtobuyabighouse?Heneedstobuyabighouse.NeedIbuyabighouse?--Yes,youmust.--No,youneedn’t/don’thaveto.(不必要)--Yes,youdo.--No,youdon’t.用法:②表示推测“肯定，一定”:①表示义务、必要或命令:Youmustcomeearlytomorrow．---MustIfinishmyhomeworkfirst?Theymustbeathome.Thelightison.---Yes,youmust.---No,youdon'thaveto/needn't.must开头的疑问句，其否定回答通常用don‘thaveto或needn’t。而不用mustn't③否定时表示“禁止”:Youmustn’tsmokehere.用法:It’seleveno’clock.Ihavetogonow.Itwasgettingdark.Hehadtofinishtheworkfirst.Idon’thavetogonow.Hedoesn’thavetofinishtheworkfirst.haveto表示客观因素Weareverygladattheparty,butit’s11,sowehavetoleavenow.must表示主观因素Wemuststudyhardtofindagoodjobforourselves.Mybrotherwasveryill,soIcallthedoctorinthemiddleofthenight.Hesaidthattheyworkhard.Youdon'thavetotellhimaboutit.Youmustn'ttellhimaboutit.你不一定要把此事告诉他。你一定不要把这件事告诉他.hadtomustCanI…?Yes,youcan.No,youcan’t.MayI…?Yes,youmay.No,youcan’t/mustn’t.NeedI…?Yes,youmust.No,youneedn’t.DoIneedto…?Yes,youdo.No,youdon’t.MustI…?Yes,youmust.No,youneedn’t.1.Mustwecleanthehousenow?No,you________.A.needn'tB.maynotC.mustn'tD.can't2.Youreturnthebooknow.Youcankeepitnextweekifyoulike.A.can'tB.mustn'tC.needn'tD.maynot3.Johnny,youplaywiththeknife,youhurtyourself.A.won't...can'tB.mustn't...mayC.shouldn't,mustD.can't...shouldn't4.______Igobackbeforelunch?No,Idon'tthinkyou________.A.Need...mustB.Do...needtoC.Must...havetoD.May....oughtto5.Theteacher____doalltheexercises,butapupil_______.A.needn't....mustB.maynot...mustC.needn't....needn'tD.can't....must6.MustIfinishthisnovelthismorning?No,you_____.A.mustn'tB.mightnotC.don'thavetoD.can't7.Thetaxi____onlyholdsixpassengers.Itisfull.You____takethenextone.A.may...mayB.can...mayC.may...canD.must...can8.Thispenlookslikemine,yetitisn't.Whose____itbe?A.mustB.canC.mayD.might