搜索
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.need1.无人称和数的变化;2.尤其用于：*否定句及疑问句中;Youneedn’tworryaboutus.有数和时态的变化NeedIsayitagain?Heneedsyourhelp.Hedoesn’tneedtodoit.YouneedtopractiseyourEnglisheveryday.Theflowersneedwatering.*或与hardly,never,noone,nobody等连用;多用于肯定句;(sb.)needtodosth.needtobedonesth.needdoing情态动词+动词原形实义动词+todosth.(否定句中可以省略to)dare主要用于否定句和疑问句．Dareyouaskhim?Idarenotgothere.Thatwaswhyhedareddoso.有数和时态的变化Shedoesn’tdare(to)gotherealone.Doyoudaretosayso?有过去时dared注意对need问句的回答:--NeedIfinishtheworktoday?--Yes,________________.No,________________.No,________________.youmustyouneedn’tyoudon’thavetoneedn’t对其它情态动词的回答:--ShallItellJohnaboutit?--No,you__________.--Mustwedoitnow?--No,you__________.needn’t(don’thaveto)needn’t(don’thaveto)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。mustn’t不准,禁止needn’t没必要(=don’thaveto)can’t不能;不可能maynot不可以;可能不shouldn’t不应该(=oughtnotto)musthavedonecanhavedonecouldhavedonemay/mighthavedone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Itis6o’clock.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.Idon’tknowwhyshedidn’tcallmeyesterday.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should(oughtto)havedoneshouldn’thavedonemighthavedonecouldhavedoneneedhavedoneneedn’thavedone本应该做而实际上没有做Youshouldhavegoneoveryourlessons.Youshouldn’thavewatchedTVlastnight.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Youneedn’thavecometowork.It’sSundaytoday.Youshould/oughttohavetoldherthetruthearlier.Sheshouldn’thaveleftwithoutsayingaword.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/needn’thavedone---Didyouanswerthephoneyesterday?---Yes,Idid.---Butyouneedn’thaveansweredit.