情态动词canmaymustneed解析区别练习

情态动词,can,may,must,need,(能),(可以),(需要),(必须),情态动词,情态动词后面+动词原形,情态动词没有人称和数的变化,1,can,Icannotplaybasketball.,Ineedbuy/boughtacomputer.,2,(能),need,(需要),Shecan/cansrideahorse.,Amyneed/needsbuyabook.,-,-,-,-,3,否定式构成是在情态动词后面加not,Icanplay/playedbasketball.,-,can,(能),用法:,表示能力:,HecanspeakalittleEnglish.,Canyoufly?,表示请求或允许:,CanIhelpyou?,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can,CouldIcometoseeyoutomorrow?,Yes,youcan.（否定答语可用No,Imafraidnot.）,注意,用法:,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mustnt或cant.(2)在疑问句中不用于第二人称,表示可能性:,Youmayberight.,No,you_,may,(可以),Yes,youmay.,注意,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.,might,mustnt/youcant.,试比较:,Youmaynotsmokehere(不可以)语气轻,Youcantsmokehere（不能）重,Youmustntsmokehere（决不可）最重,cant,maynot,mustnt,用法:,既可以做情态动词,也可以做实意动词,实意动词(needtodosth):,情态动词(needdosth):,Ineedbuyabighouse.,need,(需要),Heneeddrivemehome.,DoIneedtobuyabighouse?,Heneedstobuyabighouse.,NeedIbuyabighouse?,-Yes,youmust.-No,youneednt/donthaveto.(不必要),-Yes,youdo.-No,youdont.,用法:,表示推测“肯定，一定”:,表示义务、必要或命令:,Youmustcomeearlytomorrow,-MustIfinishmyhomeworkfirst?,Theymustbeathome.Thelightison.,-Yes,youmust.-No,youdonthaveto/neednt.,must,(必须),注意,must开头的疑问句，其否定回答通常用donthaveto或neednt。而不用mustnt,mustnt,(禁止),否定时表示“禁止”:,Youmustntsmokehere.,用法:,Itselevenoclock.Ihavetogonow.Itwasgettingdark.Hehadtofinishtheworkfirst.,Idonthavetogonow.Hedoesnthavetofinishtheworkfirst.,haveto,(必须),注意,haveto表示客观因素Weareverygladattheparty,butits11,sowehavetoleavenow.must表示主观因素Wemuststudyhardtofindagoodjobforourselves.,must,(必须),haveto,must区别,Mybrotherwasveryill,soIcallthedoctorinthemiddleofthenight.Hesaidthattheyworkhard.,Youdonthavetotellhimaboutit.,Youmustnttellhimaboutit.,你不一定要把此事告诉他。,你一定不要把这件事告诉他.,haveto,must,hadto,must,区别,CanI?Yes,youcan.No,youcant.MayI?Yes,youmay.No,youcant/mustnt.NeedI?Yes,youmust.No,youneednt.DoIneedto?Yes,youdo.No,youdont.MustI?Yes,youmust.No,youneednt.,-,-,-,找伙伴,Exercises,1.Mustwecleanthehousenow?No,you_.needntB.maynotC.mustntD.cant2.Youreturnthebooknow.Youcankeepitnextweekifyoulike.A.cantB.mustntC.needntD.maynot3.Johnny,youplaywiththeknife,youhurtyourself.A.wont.cantB.mustnt.mayC.shouldnt,mustD.cant.shouldnt4._Igobackbeforelunch?No,Idontthinkyou_.A.Need.mustB.Do.needtoC.Must.havetoD.May.oughtto,A,C,B,C,5.Theteacher_doalltheexercises,butapupil_.A.neednt.mustB.maynot.mustC.neednt.needntD.cant.must6.MustIfinishthisnovelthismorning?No,you_.A.mustntB.mightnotC.donthavetoD.cant7.Thetaxi_onlyholdsixpassengers.Itisfull.You_take