Unit 2 Healthy eating grammar 情态动词课件(人教版必修3)

,情态动词modalverbs,可兼做行为动词的情态动词：need、dare,情态动词(+动词原形),实义动词,.,need,1.无人称和数的变化;,2.尤其用于：,*否定句及疑问句中;,Youneedntworryaboutus.,有数和时态的变化,NeedIsayitagain?,Heneedsyourhelp.,Hedoesntneedtodoit.,YouneedtopractiseyourEnglisheveryday.,Theflowersneedwatering.,*或与hardly,never,noone,nobody等连用;,多用于肯定句;(sb.)needtodosth.needtobedonesth.needdoing,主要用于否定句和疑问句,Dareyouaskhim?Idarenotgothere.Thatwaswhyhedareddoso.,有数和时态的变化,Shedoesntdare(to)gotherealone.,Doyoudaretosayso?,有过去时dared,注意对need问句的回答:-NeedIfinishtheworktoday?-Yes,_.No,_.No,_.,youmust,youneednt,youdonthaveto,neednt对其它情态动词的回答:-ShallItellJohnaboutit?-No,you_.-Mustwedoitnow?-No,you_.,neednt(donthaveto),neednt(donthaveto),2.表示否定的情态动词的用法:部分情态动词的否定式是情态动词中的考点之一。,mustnt不准,禁止neednt没必要(=donthaveto)cant不能;不可能maynot不可以;可能不shouldnt不应该(=oughtnotto),表示对过去发生的事情的肯定推测，意为“一定已经”,只用于肯定句,Itis6oclock.Shemusthavecomehome.,表示对过去发生的行为的怀疑和不肯定通常用于否定句和疑问句couldhavedone也可用于肯定句.,Idontknowwhyshedidntcallmeyesterday.Can/Couldshehaveforgottenmynumber?,常用于肯定句和否定句意思为也许已经.,Heseemstoknowthecityquitewell.Hemayhavebeentherebefore.,情态动词havedone表示对过去发生的事情进行推测,表示对过去发生的事情或动作责备或抱怨的语气,本应该做而实际上没有做,Youshouldhavegoneoveryourlessons.YoushouldnthavewatchedTVlastnight.,本不应该做某事而实际上做了,本来可以做但实际上没有做,youmighthavegivenhimmorehelp,thoughyouwerebusy.,本来能够做而实际上没做,WhydidyoustayatahotelwhenyouwenttoNewYork?Youcouldhavestayedwithyouruncle.,本来有必要做而实际上没做,本来没有必要做而实际上做了,Youneednthavecometowork.ItsSundaytoday.,Youshould/oughttohavetoldherthetruthearlier.Sheshouldnthaveleftwithoutsayingaword.,4.should/oughttohavedone表示责备或批评,意为“本应该做到但没有做到”,用于否定则表示“本不该但”oughtto的语气更强烈.,Good-bye!,needhavedone/ne