英语语法 情态动词及练习题 5页

情态动词一、知识梳理/提炼1.can和could的用法表示能力或客观可能性，还可以表示请求和允许。如：Canyoufinishthisworktonight?Mancannotlivewithoutair.—CanIgonow?  —Yes,youcan.注意：①could也可表示请求，语气委婉，主要用于疑问句，不可用于肯定句，答语应用can（即could不能用于现在时态的简略答语中）。如：  CouldIcometoseeyoutomorrow?  Yes,youcan.（否定答语可用No,I"mafraidnot.）     ②can表示能力时，还可用beableto代替。如：  I"llnotbeabletocomethisafternoon.2.may和might的用法1)表示许可。表示请求、允许时，might比may的语气更委婉一些，否定回答时要用mustn"t表示“不可以”、“禁止”、“阻止”之意。如：Youmaydrivethecar.—MightIuseyourpen?  —No,youcan’t/mustn"t.Yes,youcan/may.用MayI...征询对方许可在文体上比较正式，在口气上比较客气。在日常口语中，用CanI...征询对方意见在现代口语中更为常见。2)用于祈使句中表示祝愿。如：祝你成功！Mayyousucceed!3)表示推测、可能（疑问句不能用于此意）。他现在可能很忙。Hemaybeverybusynow.3.must和haveto的用法1)表示必须、必要。如：Youmustcomeintime.回答must引出的问句时，如果是否定的回答，不能用mustn"t，而要用needn"t或don"thaveto。—Mustwehandinourexercisebookstoday?—Yes,youmust.No,youdon’thaveto/needn’t.2)“mustbe+表语”的结构表示对现在的推测，它的否定或疑问式用can代替must。  这肯定是你的笔吧。Thismustbeyourpen.3)haveto的含义与must相似，两者往往可以互换使用，但haveto有各种形式，随have的变化而定。must与haveto有下列几点不同：①must表示的是说话人的主观看法，而haveto则往往强调客观需要。如：Theplayisnotinteresting.Ireallymustgonow.我现在必须得走了我在你这么大的时候必须得工作。IhadtoworkwhenIwasyourage.②must一般只表现在，haveto则有更多的时态形式。③二者的否定意义不大相同。如：Youmustn"tgo.你不准去。Youdon"thavetogo.你不必去。5 4.need的用法1)need表示“需要”或“必须Youneedn’tcomesoearly.—NeedIfinishtheworktoday?—Yes,youmust/haveto/should/oughtto.2)need也可以做实义动词，表示“需要”，人做主语时，为sb.needtodo,物做主语时为sth.needdoing或sth.needtobedone.如：Thegardenneedswatering/tobewatered.Idon"tthinkyouneedtoworryaboutthis.5.dare的用法1）dare作情态动词时，主要用于疑问句、否定句和条件从句中，一般不用在肯定句中。如：HowdareyousayI"munfair.Hedaren"tspeakEnglishbeforesuchacrowd,darehe?2）dare可以做实义动词，敢;胆敢[+to-v]，如：Hedidnotdaretoleavehiscarthere.6.shall和should的用法1）shall用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。如：Shallwebeginourlesson?Whenshallhebeabletoleavethehospital?2）shall用于第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。如：Youshallfailifyoudon"tworkharder.（警告）HeshallhavethebookwhenIfinishreading.（允诺）Heshallbepunished.（威胁）should的含义较多，用法较活，现介绍三种其特殊用法。请看下面的句子：①Ishouldthinkitwouldbebettertotryitagain.我倒是认为最好再试一试。②Youaremistaken,Ishouldsay.依我看，你是搞错了。③Ishouldadviseyounottodothat.我倒是劝你别这样做。④ThisissomethingIshouldhavelikedtoaskyou.这是我本来想问你的。从以上例句可以看出：情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气。should还可以用在if引导的条件从句，表示一件事听起来可能性很小，但也不是完全没有可能。相当于“万一”的意思。从句谓语shoulddo，主句谓语却不一定用虚拟语气。如：⑤你万一见到她，请让她给我打个电话。Askhertoringmeupifyoushouldseeher.⑥如果你万一改变主意，请让我们知道。Ifyoushouldchangeyourmind,pleaseletusknow.⑦ShouldI(IfIshould)befreetomorrowIwillcome.此外，Why(orHow)+should结构表示说话人对某事不能理解，感到意外、惊异等意思。意为“竟会”。如：⑧你今天为何竟会来得这么晚？Whyshouldyoubesolatetoday?⑨—whereisBettyliving?—我怎么知道？HowshouldIknow?⑩我真不知道你凭什么认为这件事是我干的。Idon"tknowwhyyoushouldthinkthatIdidit.7.will和would的用法1）表示请求、建议等，would比will委婉客气。如：Wouldyoupassmethebook?2）表示意志、愿望和决心。如：Iwillneverdothatagain.Theyaskedifwewoulddothat5 again.3）表料想或猜想。如：Itwouldbeabouttenwhenhelefthome.Whatwouldshebedoingthere?Ithoughthewouldhavetoldyouallaboutit.8.oughtto的用法1）oughtto表示应该。如：Yououghttotakecareofhim.Heoughttobehomebynow.9.usedto，hadbetter，wouldrather的用法1）usedtodo过去常常做某事（现在已不做）当他小的时候他常常5点钟就起床。Heusedtogetupat5amwhenhewasyoung.Beusedtodo被用来做某事beusedtodoing习惯于做某事2）hadbetterdo意为“最好做某事”，后接不带to的不定式。如：—Wehadbettergonow.—Yes,wehad(we"dbetter/wehadbetter).3）wouldratherdo意为“宁愿做某事”，表选择。如：我宁愿现在什么也不说。I"drathernotsayanything.你宁愿在农场工作吗？Wouldyouratherworkonafarm?10．情态动词的现在完成式的用法情态动词现在完成式主要有两个功能：表示已经发生的情况和表示虚拟语气。在这两个方面must/mustn’t;can/can’t;need/needn’t;may/mayn’t;might/mightn’t;should/shouldn’t;ought等情态动词＋完成式表示的意思是有一定区别的表示已经发生的情况：1）“must+have+过去分词”的结构常用在肯定句中，表示过去肯定应经发生过某事。它的否定或疑问式用can代替must。如：他一定是去过上海。HemusthavebeentoShanghai.2）may/mighthave+过去分词，表示对已发生的事情做不肯定、可能性很小的推测，译为“过去也许发生过某事”。如：他可能已经把真相告诉他妻子了。Hemighthavetoldhiswifethetruth.3）couldn’thavedone,过去不可能做过某事。Hecouldn’thavedonethat.4）couldhavedone过去可能做过某事。表示虚拟语气1）needn’thave+过去分词，表示做了不必做的事，译为“本没必要做某事”。如：你本来不需要等我的。Youneedn"thavewaitedforme.2）shouldhave+过去分词，表示应该做某事但实际上未做，译为“本应该做某事”；shouldnot+have过去分词表示本不应该做某事但实际上做了，译为“本不应该某事”。如：我本来应该提前仔细地计划好一切的。Ishouldhaveplannedeverythingaheadcarefully.我本来不应该对他态度那么不好的。Ishouldn’ttreatedhimsobadly/rudely.2）would+have+过去分词表示过去本来会...(但没发生)，主要用于第二、三人称，表示对已经完成的动作或事态的推测。如：截止到那时，宾客们本来应该到了。Theguestswouldhavearrivedbythattime/bythen.4）couldhavedone,过去本可能做某事但未做。我本来可以赢这个游戏的，但我后来决定让她赢。Icouldhavewonthegamebutdecidedtoletherwin.5）couldn’thavedone,过去本不可能做成某事。要是没有你的帮助，我是不可能成功的。Withoutyourhelp,Icouldn’thavesucceeded.5 例题1.Asitturnedouttobeasmallhouseparty,we______soformally.A.needn’tdressupB.didnotneedhavedressedupC.didnotneeddressupD.needn’thavedressedup例题2.Mary_____myletter;otherwiseshewouldhaverepliedbeforenow.A.couldn’thavereceivedB.oughttohavereceivedC.hasreceivedD.shouldn’thavereceived例题3.______youcontinueyoureffortandsucceed!A.mustB.canC.shouldD.may例题4.—Whatdoesthesignoverthereread?—Noperson________smokeorcarryalightedcigarette,cigarorpipeinthisarea.A.willB.mayC.shallD.must例题5.You______washedsomanyclothes,we’llhaveawashingmachinetomorrow.A.musthaveB.needn’tC.needn’thaveD.couldn’thave巩固练习1I____liketomakeasuggestion.A)couldB)wouldC)mustD)might2.John"sscoreonthetestisthehighestintheclass;he____lastnight.A)shouldstudyB)shouldhavestudiedC)musthavestudiedD)musthavetostudy3.Theroomisinaterriblemess;it____cleaned.(CET-4)A)can"thavebeenB)shouldn"thavebeenC)mustn"thavebeenD)wouldn"thavebeen4.Nobodyknowshowpeoplefirstcametotheseislands.They____fromSouthAmericaonrafts.A)musthavesailedB)cansailC)mighthavesailedD)shouldhavesailed5.Marywasnotinherbedroomyesterdayafternoon.She____inherclassroom.A)shouldhavebeenB)musthavebeenC)mustbeD)shouldbe6.Ashehadheartattack,hewastoldthathe____continuethework.A)needn"tB)maynotC)mustn"tD)can"t7.You____totowntoseethefilmyesterday.ItwillbeonTVtonight.A)needn"tgoB)hadbetternotgoC)shouldnotgoD)needn"thavegone8.We____theletteryesterday,butitdidn"tarrive.A)mustreceiveB)oughttoreceiveC)musthavereceivedD)oughttohavereceived9.Withalltheworkonhand,he____tothecinemalastnight.A)mustn"tgoB)shouldn"thavegone　C)couldnotgoD)couldn"thavegone10.Evewaslateforclassagain.She____earlier.A)shouldgetupB)mustgetupC)needtogetupD)shouldhavegotup11.Iamfeelingsick.I____somuchchocolate.A)needn"thaveeatenB)couldn"thaveeatenC)mustn"thaveeatenD)shouldn"thave5 eaten12.Theroadwasmuddy.It___lastnight.A)mustrainedB)musthaverainedC)mustberainedD)couldhaverained13.Iknowthingsarehardwithyou,butyou____trytogetoverthedifficulties.A)canB)mayC)mustD)ought14.Youshouldbearinmindthatheisnotsostrongashe____.A)wasusedtobeB)usedtobeC)wasusedtoD)useto15.Mary____myletter,otherwiseshewouldhaverepliedbeforenow.A)shouldhavereceivedB)hasreceivedC)couldn"thavereceivedD)oughttohavereceived16.I____youavaluablepresentforyourbirthday,butIwasshortofmoney.A)wouldhavelikedtogiveB)likedtogive　　C)havelikedtogiveD)wouldliketogive17.“Where____myumbrella?”“Somebody____itawaybymistake.”A)is,musthavetakenB)is,musttakeC)havebeen,musttakeD)is,takes18.Tom____betterthantoaskDickforhelp.A)shallknowB)shouldn"tknowC)hasknownD)shouldhaveknown19.You____yourtoothpulledoutbeforeitrotcompletely.A)hadbettergotB)hadtogetbetterC)hadbettertogetD)hadbetterget20.Whenwegottothecinema,thefilmhasn"tstartedyet,sowe____.A)needn"thurryB)didn"tneedhurryC)needn"ttohurry　D)needn"thavehurried例一-例五DADCCBCACBCDDBDDBCBCAADDD5