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ModalVerb情态动词的语法特征1.情态动词不能单独做谓语。2.情态动词没有人称，时态和数的变化，但有些情态动词，如can,may,will,dare也有一般式和过去式的变化。Mv情态动词的个数（15）①（4组）can/could,may/might,shall/should,will/would②（4对）haveto,hadbetter,oughtto,usedto③（3个）must,need,dare考点一：情态动词的基本用法（一）can/could•1.表能够做某事（具备某种能力）；could主要指过去能够…Twoeyescanseemorethanone.Couldthegirlreadbeforeshewenttoschool?•2.表许可；用于疑问句中表请求（could表示的语气更加委婉）；用于否定句中表不允许。CanIhavealookatyournewpen?Youcan’twearjeansatwork.•3.表可能性或推断，多用于否定或疑问句中；•若用于肯定句中表常有的行为和情形，意为“有时会；时而可能”Thatcan’tbeMary---she’sinNewYork.(用于否定句中表某事肯定不真实。)Hecanbestubbornsometimes.Itcanbecoldhereinwinter.•4.表疑惑或惊讶等情绪；意为“究竟能；难道会；到底是”Whatcantheybedoing?他们究竟在干些什么？Wherecanshehaveputit?她到底把它放哪了？（二）must1.must用于肯定句中表说话人的意志或义务；或坚决要求某人做某事；否定mustn’t表禁止•Imustgotothebankandgetsomemoney.•Carsmustn’tparkinfrontoftheentrance.2.在以must开头的疑问句中，肯定回答用must;否定回答用needn’t或don’thaveto•—Mustwehandinourexercisebooksnow?•—Yes,youmust./No,youneedn’t./No,youdon’thaveto.•3.表示可能性或肯定的推断。意为“想必、准是、一定”等，只用于肯定句。Hemustbeill.Helookssopale.She’swearingadiamondnecklace.Shemusthavealotofmoney.•4.表说话人生气或不满的情绪，意为“偏要；非得”----Mustyouinterruptnow?Can’tyouseeI’monthephone?----Sorry,sir,butit’surgent.•5.用于短语ifyoumust(dosth)，表虽然不赞同但可允•许，意为“如果你一定要的…的话”----CanIsmokehere?----Ifyoumust.（三）will/would•1.表意愿，用于各种人称的陈述句Iwilldoanythingforyou.Theywon’tlendusanymoremoney.•2.表请求允许，用于疑问句Willyousendthisletterforme,please?Wouldyoumindleavingmealoneforafewminutes?•3.表习惯Shewilllistentomusic,aloneinherroom,forhours.Hewouldspendhoursonthetelephone.•4.主语为物时，多用于否定句中，意为“不起作用”Thedoorwon’topen.（四）may/might•1.表允许，might可以指过去时间，也可指现在时间，语气更委婉。Youmaytakewhateveryoulike.May(Might)Iaskforaphotoofyourbaby?•2.表可能（事实上）。might可以指过去时间，也可以指现在时间，但语气更加不肯定。Hemaybeathome,butI’mnotsure.Shemay/mightnotknowaboutit.3.may还可表祝愿•Mayyousucceed!（五）shall•1.shall用于二、三人称的陈述句，表“命令、威胁、警告、强制、允诺、决心”等YoushalldoasIday.(命令)Youshallhavemyanswertomorrow.(允诺)Nothingshallstopusfromcarryingouttheplan.(决心)•2.shall用于一、三人称的疑问句，表征询意见或请求允许,多与I或we连用Whatshallwedothisweekend?•3.shall常用于主语是第三人称的条约、法律法规、规章制度等文件中表“义务”或“规定”Oneofourrulesisthateverystudentshallwearschooluniformwhileatschool.（六）should1.表义务,意为“应该”（某件事宜做），用于各种人称。Youshouldbepolitetoyourteachers.Youshouldn’twasteanytime.•2.表推测，意为“想必一定、照说应该、估计”等。Thefilmshouldbeverygoodasitisstarringfirst-classactors.Theyshouldbehomebynow.•3．（表示不确定）万一。IfIshouldseehim,I'lltellhim.Ifitshouldraintomorrow,thesportsmeetingwouldbepostponed.4.should可以用来表示意外；常意为“竟然；居然”Ifinditastonishingthatheshouldbesorudetoyou.(七)oughtto表义务，意为“应该”（因责任、义务等该做），口气比should稍重。Youarehisfather.Yououghttotakecareofhim.Yououghtn’ttosmokesomuch.（八）usedto\hadbetter\haveto1.usedto表示过去的习惯动作或状态（现已不复存在）Hetoldusheusedtoplayfootballwhenhewasyoung.疑问句:Didyouusetogothere?/Usedyoutogothere?否定句:Ididn’tusetogothere./Iusedn’ttogothere.反意疑问句或简略回答:Sheusedtobeveryfat,didn’tshe?/usedn’tshe?--Didyouusetoplaychess?--Yes,Idid.--Usedyoutogetupearlyinthemorning?--Yes,Idid./Yes,Iusedto.双性动词need,dare,dared1.need可以作实义动词或情态动词。eg:Weneedtofinishthejobbeforedark.Youneedn’thurryasthere’splentytimeleft.2.dare,dared可以作实义动词或情态动词。eg:Hedaredtotravelabroadwhenhewasyoung.Howdareyouletyourlittlechildgooutalone?如何分辨是实意动词或情态动词？有没有加s；有没有加助动词；有没有加to；有没有在句首；有没有加not；考点二：表推测的情态动词1.对现在或客观事实的肯定的推测Must：肯定；准是；想必是Should：很可能；应该…。指按常理推测May/might：也许；大概；表示把握不大的推测Can/could：用于疑问句表怀疑----WhatareyoudoingthisSaturday?----I’mnotsure,butImight/maygotothecinema.---Goodmorning.I’vegotanappointmentwithMissSmithinthePersonnelDepartment.---Ah,goodmorning.You______beMrs.Peters•A.mightB.mustC.wouldD.can2.对现在情况或客观事实的否定推测can’t：不可能；推测的语气相当有把握couldn’t：也可表不可能；语气较委婉may(might)not:可能不；也许不，表推测的语气不是很有把握Itcan’tbethepostmanatthedoor.It’sonlyfiveo’clock.3.对过去情况的推测musthavedone:过去一定做过某事can’thavedone/couldn’thavedone:过去不可能做某事can/couldhavedone:过去可能做过某事may/might(not)havedone:过去可能（没）做过某事Sincenobodygavehimanyhelp,he____havedonetheresearchonhisown.A.canB.mustC.wouldD.needWhyareyoureyessored?You______havesleptwelllastnight.A.can’tB.mustn’tC.needn’tD.won’t三．情态动词+havedone的其他用法should/oughttohavedone表过去本该做…却没有做shouldn’t/oughtnottohavedone表过去本不该做…却做了couldhavedone表本可以/本可能做某事却没做mighthavedone表本可能但实际没有发生的事needn’thavedone表本来不需要做却做了•Hetaughtusduringthelunchbreaksandtheeveningwhenheshouldhavebeenasleep.•Youneedn’thavetakenataxi,foritwasveryneartomyhouse.•We_____thedifficultytogether,butwhydidn’tyoutellme?A.shouldfaceB.mightfaceC.couldhavefacedD.musthavedone