高中英语必修三情态动词语法

高中英语必修三情态动词（unit1，unit2）一、情态动词的特点:1.没有人称和数的变化。2.有些情态动词有过去式的变化:e.g.will→would,can→could,may→might,dare→dared二、情态动词的否定式:情态动词+not+动词原形cannot:can't,mustnot:mustn't,neednot:needn't三、情态动词的用法及相互区别,是考试的内容之一1.can,beabletobeableto表示经过努力后,能够做到;beableto有多种形式的变化。can1).表示体力或脑力方面的能力;2).表示允许、可能性。could是can的过去式,表示过去有能力及过去存在的可能性;用于疑问句表示委婉地提出问题。1)Thefirespreadthroughthehotelveryquicklybuteveryone____getout.(NMET97)A.hadtoB.wouldC.couldD.wasableto2)-Willyoustayforlunch?-Sorry,__.Mybrotheriscomingtoseeme.(NMET99)A.Imustn'tB.Ican'tC.Ineedn'tD.Iwon't2.may表示询问或说明一件事可不可做;表示某事有可能发生。might是may的过去式;用在疑问中比may委婉、客气。1)-MayItakethisbookoutofthereading-room?-No,youmustn't.(Yes,youmay.)2)-MightImakeasuggestion?-Yes,youmay.3.must1).表示必须要做的事:必须2)表示很有把握的推断:一定,准是。have(has)to:have(has)gotto必须,不得不。过去式:hadto3)-MustIgettothestationbeforethreeo'clock?-Yes,youmust.(No,youneedn't.)4)I'mafraidyouwillhavetowaitawhile.5)Shemustbeintheclassroomnow.6)Mary____beinParis,Isawherintownonlyafewminutesago.(NMET94)A.mustn'tB.shouldn'tC.can'tD.maynot4.shall1)在疑问句中,用于第一、三人称表示说话人征求对方的意见或向对方请求。2)用于二、三人称,表示说话人给对方的命令、警告、允诺等概念。1)-ShallIplaceanorderwithyounow?-No,youneedn’t.-Shallheturndowntheradioabit?-Yes,please.(No,pleasedon't.)2)YoushallhavetheEnglishbookassoonasIfinishit.3)Everythingthatheownsshallbetakenawayfromhim.4)Yourbrotherseldomcomestoseeyou,____?A.doesheB.doesn'theC.willheD.isn'the5)It'safineday.Let'sgofishing,____?A.won'tweB.willweC.don'tweD.shallwe5.should应该;应当1)Youshouldlistentothedoctor'sadvice.2)Youshouldstudythearticlecarefully.6.will,would1)在疑问句中用于第二人称,表示说话人向对方提出请求或询问。用would语气更加婉转。2)will表示现在的习惯性动作或状态;would表示过去的习惯性动作或状态。3)will用于各种人称,表示意志、意愿、决心、允诺;would表示过去时间的意志、意愿、......。(1)Don'tsmokeinthemeetingroom,___you?A.doyouB.willyouC.canyouD.couldyou-Willyoucomewithme?-Yes,Iwill.(Iamsorry,Ican't.)(2)-Wouldyoutellussomethingaboutyourself?-Yes,Iwill.(3)-It'smybirthdaytomorrow.Don'tforgettocometomyparty.-_____.A.Idon'tB.Iwon'tC.Ican'tD.Ihaven'7.oughtto应该;应当1)Yououghtn'ttosmoketoomuch.2)She____forwhatshehasdone.A.oughttopraiseB.oughtbepraisedC.oughttohavepraisedD.oughttobepraise8.dare1.daretocome2.darecome1)Hedarenottellthetruth.2)Hedoesn'tdaretocomeoutatnight.3)Idon'tknowwhetherhe____try.A.dareB.needsC.wantsD.isallowed9.need1).作为情态动词:必须2).作为实义动词:需要A.主语是人need(todosomething;tobedonebysomebody)B.主语是事物need(doing;tobedone)1)-Dotheyneedtotakeanybookswiththem?-No,theydon'tneedto.2)-Needwebuyanynewequipment?-No,weneedn't.3)Thisfarmtoolneedsrepairing.Thisfarmtoolneedstoberepaired.4)-ShallItellJohnaboutit?-No,you___.I'vetoldhimalready.A.needn'tB.wouldn'tC.mustn'tD.shouldn't5)It'safineday.You____takearaincoatwithyou.A.can'tB.mustn'tC.needn'tD.maynot情态动词+不定式的完成式是高考的考试要点1、musthavedone,“一定做过/一定已经．．．”，表示对过去情况极大把握地推测，仅用于肯定句2、may/mighthavedone也许做过某事（推测）；本来可以做某事却没做3、can'thavedone为否定句或疑问句,对过去的推测“不可能，一定没做过某事”couldhavedone本来可以做某事却没做4.needn’thavedone表示”不必要做某事，但做了”，而needn’tdo则表示”不必做(也没做)”5.、oughtto/shouldhavedone表示”本来应当做的却没做”oughtn’t/shouldn’thavedone本来不应该做某事却做了6、would/could/might/should+havedone用来表示与过去事实相反的虚拟语气7、wouldratherhavedone表示”当时宁愿做了某事”，否定形式：wouldrathernothavedonee.g.IfIhadbeenfreethatday,Iwouldhavegonewithyou.8、wouldlike/lovetohavedone表示”本想做某事”而实际上未做。