情态动词的特点ppt课件

Grammar:Modalverbs,LecturedbyRenQiuyu,1,一、情态动词的特点,1有词义2没有人称和数的变化。也就是说，它在任何主语后形式都是一样的，这是情态动词和助动词最大的差异。3有时态的变化4不能独立作谓语，后面必须跟动词原形在情态动词后一般要跟不带to的不定式（oughtto除外）,2,二、情态动词的种类,3,1)can表示体力、智力上的能力。否定式为cannot,缩略为cant;过去式为couldcouldnteg:Wecandothingstheycantdo.Marycantypewellandhermothercouldtypewellwhenshewasyoung.2)表示客观可能性eg:Mancannotlivewithoutair.3)表示征求意见或请求许可，表示语气委婉eg:CanIgoforaswimthisafternoon,Mum?Couldyoulendmeyourbicycle?No,sorry,Icant.(couldntiswrong)Yes,ofcourseyoucan.,1.can和could,4,4)can和could表推测（can用于否定及疑问,could肯定、否定、疑问皆可）can(could)not+V原（link.或状态动词）对现在状态的推测can(could)not+be+doing对现在动作的推测can(could)not+havedone对过去动作的推测eg:a.Theyounggirlcantbeournewchairman.Can/Couldthenewsbetrue?b.Hecantbereadinginthereadingroom,forIsawhiminthestreetjustnoTheymaybearguing.ButIaminterestedinwhattheycan/couldbearguing.c.Theroadisntwet.Itcant/couldnthaverainedlastnight.Idontknowwhyshedidntcallmeyesterday.Can/Couldshehaveforgottenmytelephonenumber?5)couldhavedone本能做却没有做,canhavedone这种结构不存在eg:Youcouldhavecaughtthefirsttrain,butyougotuptoolate.,5,6)Can/could与beableto的区别A.beabletodosth.也表示能力，可以用于不同时态，前后还可以用情态动词must,may,might以及seemto,usedto,appearto等，而can/could只用于一般现在时和一般过去.eg:Heisableto(=can)playthepianoverywell.Afterthreeyearsofhardwork,hewasabletopasstheentranceexamination.Thelargehallwillbeabletohold5000audience.Heseemstobeabletoworkoutthepuzzlingquestion.B.当用于过去时态时，could表示能力，但有没有做，不知；而was/wereableto指过去某种具体的能力，通过努力并做成功了，相当于managedto或succeededineg:HecouldsingmanyEnglishsongs.Itsknownthathewasabletorecitemanyforeignpoemsatsix.,6,1)may表示请求许可。疑问式MayI.?多为请求允许，通常用于正式文体egMayIcomein?No,youcant/maynot.Yes,please.No,youmustnt.(强烈禁止，不允许)Yes,certainlyPleasedont.Sure.Might也可以表示允许，MightI?和MayI.?用法相近.但might表示请求语气迟疑委婉，回答时应用may表示肯定eg:-MightIaskforaphotoofyourfamily?-Yes,youmay.2)may用在句子开头，表示祝愿May+主语+动词原形+其它成分eg:Mayyousucceedinthecomingexamination!Mayallyourdreamscometruesomeday!,2.may和might,7,3)may和might表推测（不用于疑问）may/might+V(系动词或状态性动词)对现在状态的推测may/might+bedoing对现在动作的推测may/might+havedone对过去动作的推测eg:a.HemayknowAlicesaddress.HemaynotknowAlicesaddress.（可能不）HecantknowAlicesaddress.（不可能）Canitbetrue?Itmaybe,ormaynotbe.b.WheresTom?Hemay/mightbeplayingfootball.c.-Heseemsknowthecityquitewell.-Hemay/mighthavebeentherebefore.,8,1)表示必要性、义务，“应该”、“必须”的意思，否定式mustnt表示不允许egYoumustwaitforyourturn.Youmustntjumpthequeue.MustIbehomebeforeeightoclock?-Yes,youmust.(No,youneednt./No,youdonthaveto.)2）haveto和must意义相近，意为“不得不”，含有“客观需要使得必须这样做”的意思，有时态、人称的变化,havegotto用于口语，donthaveto为否定式，意为“不必要”egShedidnthavetosaysorry.Dowehavetoanswerallthequestions?NextyearIwillhavetoleavethisschool.3）must表推测（一般用于肯定句）意为：一定否定式：cantmust+Vmust+bedoingmust+havedoneeg:情态动词must猜测性的反义疑问句Hemustbeadoctor,isnthe?（表现在状态，用be）Hemustlivenearhere,doesnthe?（表现在动作，用do,does）Hemusthavecomehereyesterday,didnthe?（表短暂性过去动作，用did）TheymusthavebeentoBeijing,haventthey?（表现在状态，用have,has）,3must和haveto,9,4will/would;shall,1)will表示意志意愿，用于各种人称，可译为“肯”、“会”、“愿意”等，过去式为wouldegIfyouwillallowme,Iwillseeyouhome.Iwillhavenothingtodowiththismatter.Nomatterwhathappened,hewouldntsayaword.Ifhekeptonmakingmistakes,Iwouldntmakefriendswithhim.2)will用于第二人称，表示有礼貌的请求，would为过去式，但语气更委婉egWillyoukindlyhandmethewatch?Bringthefruittothedining-room,willyou?-Wouldyoudomeafavor?-Yes,Iwill./Sure/Ofcourse/Certainly.No,Iwont./ImsorryIcant.Will/WouldyoupleasedoWouldyouliketodosth.wouldratherdosth.(thandosth.),10,3)woulddo(usedtodo)表示过去常常做某事,would后只能接动作性动词而usedto既可以接动作性动词，也可以接状态性动词。Hewouldgotoenjoysomewonderfulfilmsatnight.Heusedtobeateacher.4)wouldhavedone用于虚拟，与过去事实相反Ifyouhadhelpedus,wewouldhavefinishedourhomeworkaheadoftime.5）shall用于第一、第三人称疑问句中，表示说话人征求对方意见或向对方请示。egShallwegoandgetsomefood?Whenshallhebeabletoleavethehospital?Shall用于第二、第三人称，表示说话人给对方的命令、警告、允诺或威胁。eg.Youshalldoit./Heshallstayathome.（命令）Youshallfailifyoudontworkhard.（警告）HeshallhavethebookwhenIfinishreading.（允诺）Heshallbepunished.（威胁）,11,5should/oughtto,两者意义基本相同，用法也相同1）表示劝告或建议，should语气比oughtto弱，意为“应该”，否定式shouldnt,oughtnotto意为“不应该”egYoushouldgeteverythingreadybeforetheexamination.Heshouldntbesocareless.Weoughttobeoutinthefreshair.Weoughtnottotakerisks（冒险）.2）表示应该怎么样却没有怎么样A.对现在进行动作should(oughtto)bedoing/shouldnt(oughtnotto)bedoingeg:Youshouldbewashingyourclothes.Whyareyouplayingfootball?Youareill.YoushouldntbeworkinghereB.对过去动作Should(oughtto)havedone(本应该做却没有做)Shouldnt(oughtnotto)havedone(本不应该做却做了)eg:Youshouldhavegoneoveryourlessons.Ishouldnthaveeatensomuchicecream.3)should表推测，暗含很大的可能或有根据有把握Thefilmshouldbeverygood.Thephotoshouldbereadytomorrow.,12,6need,可以既作情态动词又作实义动词1)need用作实义动词，用在肯定句、否定句和疑问句中，有人称变化和过去时形式，后接名词、代词、动名词和动词不定式egSheneedsmorerest.Youdidntneedtotellhimthenews.TheTVneedsmending/tobemended.2)need作情态动词时一般只用在否定句或疑问句中，没有人称和时态的变化eg-Needwetellhimaboutit?-No,youneednt/donthaveto.Youneedntfinishwritingthereportinsuchashorttime.Hesaidheneednotgoyesterday.3)neednthavedone本不必做却做了needhavedone几乎不存在这种结构Timeisenough.Youneednthavecomeinsuchahurry.,13,7dare,可以既作情态动词又作实义动词1)dare用作实义动词，用在肯定句、否定句和疑问句中，有人称变化和过去时形式，dare(s/d)todosth,但在否定句中，后面的不定式可带to,也可不带toegHewassobravethathedaredtogoaloneatnightattheageoffive.Hedoesnotdare(to)answerhisfathersquestion.Doyoudaretotouchit?2)dare作情态动词主要用于否定句、疑问句或条件句中，没有人称的变化，但是有过去式dared，但Idaresay（常用作插入语）除外egHisspeechisquiteexcellent,Idaresay,whichwillwinhimthefirstprize.HowdareyousayIamaliar?Noonedaredspeakaboutit.Idarentaskyou,becauseIthoughtImustbewrong.Ifyoudaredothatagain,theteacherwillscoldyou.,14,情态动词的猜测性用法总结,我们用must（一定）,can（可能）,could（可能）,may（也许）,might（或许）表示“猜测可能性”。Could,might比can,could在口气上要委婉些。可能性由大到小排列为：mustcan(could)maymight,15,1）对现在或将来的猜测Modal.Verb+(not)dosthShemust/may/mightknowLilysaddress.Hemust/may/mightleaveforBeijingtomorrow.Hecant/couldnt/maynot/mightnotbeabletopaythehouse.-Itsnotmine.Whosecan/coulditbe?（疑问句中一般不用may,might）-ItcouldbeJohns./Itcant/couldntbeJims.2）对现在进行的动作的猜测Modal.Verb+(not)bedoingsthTheymust/may/mightbewaitingattheschoolgate.HecantbereadingintheclassroomforIsawhiminthestreetjustnow.Shecant/maynot/mightnotbeeatinganythingnow.3）对过去动作或已经完成的猜测Modal.Verb+(not)havedonesthHemust/may/mighthavemademuchprogressrecently.Hecant/couldnt/maynot/mightnothavefinishedhishomework.Can/Couldhehavegotwhathewanted?,16,注：1must作为猜测只能用于肯定句，mustnt表示不能，不许，不是猜测2can作为猜测只能用于否定句，疑问句，但could可用于肯定句、否定句和疑问句3canhavedone,mustnthavedone作为猜测不存在，couldhavedone表示本能做却没有做4may,might作为猜测一般不用于疑问句,17,1、Englishisalanguagethatmanypeoplearoundtheworldnotspeakperfectlybutatleast_understand.A.may;canB.would;mightC.will;mustD.could;might,【答案解析】根据句意和句子的语气可知，第一空表示一种可能性，用maynotspeak可能不会说；第二空表示有某种能力。答案A。,2、Didnttheycometothepartylastweek?Yes.Theydidntwanttocomewithusatfirst,butthenwe_persuadethem.A.WouldB.couldC.wereabletoD.hadto,【答案解析】根据上下文语境及讲话人语气，选项动作表示经过努力才完成的。在这种语气的肯定句和疑问句中，常用beableto，在否定句中可用can。答案C。,3、Ipromiseherdaughter_getanicepresentonherbirthday.Willitbeabigsurprisetoher?A.shouldB.mustC