情态动词一.情态动词基本用法1.?can和could,用在否定句和疑问句中,表示惊讶,用在否定句和疑问句中。Howcouldyoudosuchasillything??cannot....too/enough表示“无论...也不过分,越...越好”。Youcan’tbetoocarefulwhiledriving?2.may和might的区别?表示许可、可能性、祝愿等意义,might比may更委婉。A:给别人许可时。-MayIplaybasketballthisafternoon?B:may/mightaswell+动原,“最好,倒不如”。?may作“可以”讲时,疑问句回答用mustn’t/can’t表示禁止。3.Must的用法?表示禁止(用于否定中)Youmustn’tsmokeinthebedroom.?表示偏执、固执-CouldIhaveawordwithyou,mum?-Ohdear,ifyoumust.?must的否定回答A:作必须讲时,疑问否定回答用don’thaveto,needn’tB:推测,一定讲时,回答用can’t.C:mustn’t表禁止。--MayIuseyourcar?--No,youmustn’t./-Sorry,you’dbetternot.(委婉)注意:must强调内在职责,而haveto强调迫于外界压力,不得已而为之。4.shall的用法?一、三人称征求意见时。请求对方时。Shallwebeginourclass??二,三人称陈述句中,说话人给对方的命令,警告、允诺或威胁。Youshallnotgetmysupportifyoudosuchathing.5.will和would的区别?自愿主动提出,如:意志、愿望或决心,would过去,willnot表示拒绝。Ihavetoldhimagainandagaintostopsmoking,buthewillnotlisten.?will习惯性动作,有“总是”或“总要”之意。Everythinghewillhaveawalkalongthisyear.?would过去习惯性动作,比usedto正式。LastyearourEnglishteacherwouldsometimestellusstoriesinEnglishafterClass.?usedtodo过去常,过去一直------只表示过去。beusedtodo“用来”/beusedtodoing习惯于-----可表过、现或将。6.dare表示敢于情态:daredoDareyougohomealong?及物:daretodoDotheydaretosaywhatshethinks?7.need用法情态:needdo及物needtodo表示主动needdoing被动Myovercoatsneedswashing.8.must一定要,必须,应该(现在时)haveto客观需要,能用于更多时态(过去或将来)注意oughtto表示义务和责任“应该”,比should语气强。Yououghttotakecareofyourself.二.情态动词表推测用法1.Sorry,I’mlate,Imighthaveturnedoffthealarmclockandgobackagain.2.Theaccidentcouldhavebeenavoided.3.Youshouldhavetoldmeaboutitearlier.4.Yououghtnottohavesaidsuchwordstoyourparents.5.Youneedn’thavewalkedsoquicklysincetimewasenough.6.Hemusthavecompletedhiswork,otherwise,hewouldn’tbeenjoyinghimselfbyseaside.情态动词适用场合对未来和现在推测对过去的推测(情态动词+完成体)may/might肯、否may/mightdomay/mighthavedone可能做过,本应做而实际未做。can/could否、疑Could肯can/coulddocan/couldhavedone本应做而实未做can’thavedone不肯能做过,语气强烈should肯、否、疑用来表示一种估计的情况,shoulddoshouldhavedone本应做而未做shouldn’thavedone不应该做而做了oughttooughttodooughttohavedoneoughtnottohavedoneneedneeddoneedn’thavedone本来不必而实际已经发生了must肯定句mustdomusthavedone一定发生了情态动词练习题1.(2011全国卷II,8)Ifyou______smoke,pleasegooutside.A.canB.shouldC.mustD.may2.(2011北京卷,24)——Idon’treallylikeJames.Whydidyouinvitehim?——Don’tworry.He______come.Hesaidhewasn’tcertainwhathisplanswere.A.mustnotB.neednotC.wouldnotD.mightnot3.(2011上海春招,27)someyoungpeoplethesedaysjust______gooutoftheirhomestocontacttherealworld.A.mustn’tB.won’tC.mightn’tD.shouldn’t4.(2011福建卷,25)——ShallIinformhimofthechangeoftheschedulerightnow?——Iamafraidyou______,incasehecomeslateforthemeeting.A.willB.mustC.mayD.can5.(2011安徽卷,26)——Whatdoyouthinkofstoreshoppinginthefuture?——Personally,Ithinkitwillexistalongwithhomeshoppingbut_____.A.willneverreplaceB.wouldneverreplaceC.willneverbereplacedD.wouldneverbereplaced6(2011浙江卷,11)——How’syournewbabysitter?——We__...