情态动词精讲(全)

情态动词精讲ModalVerbs情态动词是一种本身有一定的词义，但要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。基本助动词与情态助动词（两种助动词）最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想。牢记的两句话：肯定句中一定没有canhavedone的形式；Mustn’thavedone无论如何都不存在。可以表示虚拟的情态动词：could,might,should,would,need可以表示推测的情态动词：could,might,should,must,may,can(否，疑)（虚拟与事实相反，推测与事实相一致）综述：情态动词表推测的用法小结（一）情态动词表推测的三种句式1.在肯定句中一般用must(一定)，may（可能），might/could（也许，或许）,should(按理说应该)；（1）Hemust/may/mightknowtheanswertothisquestion.他一定/可能/也许知道这个问题的答案。（2）Itiscoldintheroom.Theymusthaveturnedofftheheating.屋里很冷，他们肯定把暖气关了。（3）It’sseveno’clock.Jackshould/oughttobehereatanymoment.现在七点钟了，杰克理应随时到达。（推测）2.否定句中用can’t/couldn’t(不可能),maynot/mightnot(可能不)，shouldn’t(按理说应该不)；（1）Itcan’t/couldn’tbetheheadmaster.HehasgonetoAmerica.这不可能是校长，他去美国了。（2）Hemaynot/mightnotknowthescientist.I’mnotsure.他也许不认识那位科学家。（3）Sinceyouhavemadesomanypreparationsfortheexam,thereshouldn’tbeanydifficultyforyoutopassit.既然你为考试做了这么多准备，按理说通过应该不会有任何困难。3.疑问句中用can/could(能……?)。（1）Could/Canhehavefinishedthetask?他可能把任务完成了吗？（2）Ican’tfindmywalletanywhere.Wherecan/couldIhaveputit?Could/CanIhavelostit?注：以上三种句式中情态动词的语气按程度都是依次递减的。Might,could并非may,can的过去式，而表示语气较为委婉或可能性较小。（二）情态动词表推测的三种时态（情态动词本身并无时态差别）1.对一般现在、将来情况的推测，用“情态动词+do”。（1）Hecan’t(couldn’t)/may(might)notbeathomeatthistime.这个时候他不可能/可能不在家。（2）Shemust/may/might/couldarrivebefore5.5:00前她一定/可能/也许到。2.对现在进行或将来进行的动作进行推测，用“情态动词+bedoing’。Hemust/may/might/couldbelisteningtotheradionow/thismomenttomorrow.他一定/可能/也许正在听收音机。/明天这个时候…3.对过去情况的推测，用“情态动词+havedone”。（1）Itmust/may/might/couldhaverainedlastnight.Thegroundiswet.地湿了，昨晚肯定/可能/也许下雨了。（2）Thedoorwaslocked.Hecan(could)not/may(might)nothavebeenathome.门锁着，他不可能/可能不在家。（3）Can/Couldhehavegottenthebook？难道他找到书了吗？4.对过去进行的动作进行推测，用“情态动词+havebeendoing”(也可表示对从过去开始到现在一直在进行的动作进行推测)。--Youmusthavebeendrivingatseventymilesanhour.Didn'tyouseethespeedlimit?--Ican'thavebeen.IwasdoingeightywhenIovertookyou.--Imusthavebeendreaming.情态动词的基本用法：must1).“必须”（命令，义务）Youmustworkhardifyouwanttosucceed.“必须，一定要”Youmustn’tplaywithfire!“禁止，不许”--MustIfinishmyhomeworkrightnow?--Yes,youmust./No,youneedn’t/don’thaveto.2)“非得”（坚持）--Mustyoumakesomuchnoise?Icannotconcentrate.--MayIsmokehere?--Ifyoumust,chooseaseatinthesmokingsection.3)“一定是”（推测）Hemustbeintheroom,forthelightisstillon.Hecannot/couldn’tbeintheroom,forthelightisoff.(否定形式)Theymusthaveseenusyesterday,didn’tthey?Theymusthaveseenus(before),haven’tthey?can/could“能”（能力，潜能）(有时态差别)Icanswim.beableto(潜在的能力或经努力结果能够做到均可)(否定句，两者无区别；另beableto有各种时态)can“可能”（主语的客观性质）；“有时会”（一时的可能性）Apilot’sjobcanbeboring.Themonkeylookssweet,butitcanbenaughtysometimes.TheweatherinBeijingcanbecoldinwinter.“可能”（推测）Can表推测只用于否定句、疑问句；could无要求。Can与could在表推测时无时态差别。(may和might也如此)--CanhebewatchingTVnow?--No,hecan’tbewatchingTVnow.Hecouldhavegonethere,butI’mnotsure.Ican’tfindmywalletanywhere.WherecanIhaveputit?CouldIhavelostit?4)could“本能够”（虚拟）Heboughtaticketthoughhecouldhaveenteredfree.5)could委婉（不表明时态）6)请求；许可--Could/CanIaskaquestion?(could委婉)--Ofcourseyoucan.(回答不用could,不用委婉)7)“居然，竟然”(惊讶)(疑问句、否定句、感叹句中用can/could)(详见should-4)8)反问句中，表示强烈的感情色彩。--Can’tyouseeIambusy?--I’vebeenstudyingsineeighto’clock.Can’tIgooutandplayforawhile?may/mightmay/mightaswelldosth(asdosthelse);may/mightwelldo2)“可能，或许”（推测）（无时态差别）Theremight/maybeameetingtomorrow,butIamnotsure.3)may祝愿（肯定句）（倒装）Mayyousucceed.MayGodblessyou.4)might虚拟Withoutyourhelp,wemighthavefailed.5)许可--Might/MayIaskaquestion?(might委婉)--Ofcourseyoumay.(回答不用might,不用委婉)--MayIsmokehere?(否定回答不用May，肯定回答可以)--Noyoucan’t/mustn’t./you’dbetternot./I’mafraidnot.should(=oughtto)“应该”（责任，义务；劝告，建议）Weshouldrespectourparents.2)“按理应该”（推测）Thereshouldn’tbeanydifficultyforyoutopasstheexamsinceyouhavepreparedsomuchforit.3)“本应”（责备，虚拟）Youshouldhavetoldmethenewsearlier.4)(肯定句中)“居然，竟然”(惊讶)(疑问句、否定句、感叹句中用can/could)Youcan’timaginethatawell-educatedgentlemanshouldbesorudetoalady.Thiscan’tbedonebyhim.Howcanyoubesocareless?(Howcomeyouaresocareless?)Howcouldyoufallinlovewithhim?(Howcomeyouaresoconfident?)Canthisbetrue?5)should虚拟，不能用oughtto代替Shoulditbefinetomorrow,wewould/willgoforapicnic.Itishightimethatyoushouldapologizetoher.(Br.E)Itis…youapologizedtoher.(AmEandBrE)Suggest型虚拟中，可省略shall1）二、三人称陈述句，表命令、警告、威胁、允诺、强制（考试交卷）等。Youshallhaveanewbikeifyoupasstheexam,Youshallfailtopasstheentranceexamifyoudon’tworkhard.Nocandidateshallbeallowedtocarryanyelectronicandtelecommunicationdevices.2)一、三人称疑问句，表请求，询问。（第二人称用疑问句用will）--What’sthename?--Khulaifi.ShallIspellthatforyou?Excuseme,Mr.Li,butshallEriccomeinrightnow?3)“必须”，用于法律条文，法庭上，或正式文字中。“Theinterestshallbedividedintofiveparts,accordingtotheagreementmadebybothsides,”declaredthejudge.“Shylockshallgivehalfofhismoneytothecityaccordingtothelaw.“4)Letusgo,willyou?Let’sgo,shallwe?will/would1)表功能缺陷Thedoorwouldn’t/didn’topen/shut.Theinkwon’t/doesn’tcomeout.2）表意志，意愿，愿意。I’vealreadytoldhimnottodothosesillythings,buthewouldn’tlisten.3）“常常”，习惯Shewilllistentomusicaloneinherroomforhours.Hewouldspendhoursinthebathroom.(=usedto)4）叙述真理Oilwillfloatonwater.5）表习惯，习性，倾向。”常常，易于，毕竟是，总是，惯于”--Theyarerestless.--Boyswillbeboys.Mycarwillsometimesbreakdown.偶尔出故障。6）请求，征求许可（第二人称）Will/wouldyouplease…?7）would虚拟8)will

临时决定。--Kateisill.--Oh,really?Iwillgotoseeherthen.--/IknewthatandIamgoingtoseeher.Begoingto有迹象表明要发生/有计划/一定会（预测）Look!Itissocloudy.Itisgoingtorain.Themovieisfantastic.Youaregoingtolikeit.7.need/dare(做情态动词使用很少用于肯定句)1)--NeedIwaitforyouatthegate?--Yes,youmust/haveto./No,youneedn’t/don’thaveto.(同must)2）needn’thavedone虚拟3）dare用做行为动词，否定句中，后面的不定式可省略to。Shedoesn’tdare(