高中英语语法 情态动词 6页

1比较can和beableto1）can/could表示能力；可能（过去时用could）,只用于现在式和过去式（could）。beableto可以用于各种时态。例如：　Theywillbeabletotellyouthenewssoon.他很快就能告诉你消息了。表示成功地做了某事时，用was/wereableto，不能用could。例如：HewasabletofleeEuropebeforethewarbrokeout.=HemanagedtofleeEuropebeforethewarbrokeout.2）提出委婉的请求，（注意在回答中不可用could）。例如：　　---CouldIhavethetelevisionon?我能看电视吗？　　---Yes,youcan./No,youcan‘t.可以/不可以。3）在否定句、疑问句中表示推测或怀疑。例如：Hecouldn’tbeabadman.他不大可能是坏人。Couldhehelpus?Thegirlcouldn’thavestolenyourelectronicdictionary.•4）　有时会，hecanbedifficulttogetalongwith,eventhoughheisgood　5）否定推测用can"t。例如：　　IfTomdidn"tleavehereuntilfiveo"clock,hecan"tbehomeyet.　如果汤姆五点才离开这儿，他此时一定还未到家。2比较may和might1）表示允许或请求；表示没有把握的推测；may放在句首，表示祝愿。例如：　　　　MayGodblessyou!愿上帝保佑你！　　　　Hemightbeathome.他可能在家。注意：might表示推测时，不表示时态，只是可能性比may小。2）成语：may/mightaswell，后面接不带to的不定式，意为"不妨"。例如：　　　Ifthatisthecase,wemayaswelltry.如果情况确实如此，我们不妨试一试。典型例题　Peter___comewithustonight,butheisn"tverysureyet.　A.must　　B.may　C.can　D.will•3haveto•1)haveto表示客观的需要，must表示说话人主观上的看法，既主观上的必要。例如：Mybrotherwasveryill,soIhadtocallthedoctorinthemiddleofthenight.　弟弟病得很厉害，我只得半夜里把医生请来。（客观上需要做这件事）　　Hesaidthattheymustworkhard.他说他们必须努力工作。（主观上要做这件事）2）　haveto有人称、数、时态的变化，而must只有一种形式。但must可用于间接引语中表示过去的必要或义务。例如：Hehadtolookafterhissisteryesterday.他昨晚只得照顾他姐姐。3）否定结构中：don‘thaveto表示“不必”，mustn’t表示“禁止”。例如：　　Youdon‘thavetotellhimaboutit.　你不一定要把此事告诉他。 　　Youmustn’ttellhimaboutit.　•4must•Mustyoumakeanoiseintheclassroom?•1）must用在肯定句中表示较有把握的推测，意为"一定"。　2）must表对现在的状态或现在正发生的事情的推测时，must后面通常接系动词be的原形或行为动词的进行式。例如：　　　Youhaveworkedhardallday.Youmustbetired.你辛苦干一整天，一定累了。（对现在情况的推测判断）　　　Hemustbeworkinginhisoffice.他一定在办公室工作呢。　　　　　3）must表示对已发生的事情的推测时，must要接完成式。例如：　　Ididn"thearthephone.Imusthavebeenasleep.　我刚才没有听到电话，我想必是睡着了。　4）must表示对过去某时正发生的事情的推测，must后面要接不定式的完成进行式。例如：　　---Whydidn"tyouanswermyphonecall?为何不接我的电话？　　---Well,Imusthavebeensleeping,soIdidn"thearit.唉，肯定在睡觉，所以没有听见。•5)Atthismoment,ourteachermustbecorrectingourexampapers.这时，想必我们老师正在批改试卷。情态动词+动词现在进行时，表示对现在或将来正在进行的情况进行推测。　1）情态动词+动词完成时，表示对过去情况的推测。例如：　　Theroadiswet.Itmusthaverainedlastnight.地是湿的，昨天晚上一定下雨了。　2）情态动词+动词的现在完成进行时，表示对过去正在发生事情的推测。例如：　　Yourmothermusthavebeenlookingforyou.你妈妈一定一直在找你。　3）推测的否定形式，疑问形式用can"t,couldn"t表示。例如：Mikecan"thavefoundhiscar,forhecametoworkbybusthismorning.迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。•may（might）have+donesth,can（could）have+donesth　表示过去，推测过去时间里可能发生的事情。例如：　　Philipmay（might）havebeenhurtseriouslyinthecaraccident.菲力浦可能在车祸中受了重伤。　　Philipcan（could）havepassedtheexambuthedidn’tstudyhard•4）musthave+donesth，对过去时间里可能发生的事情的推测，语气较强，具有"肯定"，"谅必"的意思。例如：　---Lindahasgonetowork,butherbicycleisstillhere.琳达已经去上班了，但她的单车还在这儿。　---Shemusthavegonebybus.肯定乘巴士去的。 5)oughttohavedonesth,shouldhavedonesth表示本应该做某事，而事实上并没有做。否定句表示“不该做某事而做了”。例如：　　Yououghtto（should）havebeenmorecarefulinthisexperiment.你当时在做试验时应该更仔细点。　　Heoughtnottohavethrowntheoldclothesaway.他不该把旧衣服扔了。（事实上已扔了。）　　oughtto在语气上比should要强•Itisstrangethatheshouldhavespokentohisteacherinthisway.•6）needn"thavedonesth表示本没必要做某事，但做了。例如：Idressedverywarmlyforthetrip,butIneedn"thavedoneso.Theweatherwashot.旅行时，我衣服穿得较多，其实没有必要。那时天很热。7）wouldliketohavedonesth表示本打算做某事，但没做。例如：　　　Iwouldliketohavereadthearticle,butIwasverybusythen.我想读这篇文章，但太忙了一直没读。•should和oughtto除了上述的用法，两者还可表示“想必一定，按理应该”的意思。例如：Ioughttobeabletoliveonmysalary.靠我的薪水，想必也能维持了。Itoughttobereadynow.想必现在准备好了吧。Theyshouldbetherebynow,Ithink.现在他们该到那儿了。Thepoemsshouldbeoutinamonthatmost.诗集估计最多还有一个月就要出版•Don’tworry.Ihavesentanambulancetoyou.Theyshouldbethereanysecond•wouldratherdo　wouldrathernotdo　wouldrather…than…　宁愿…而不愿。　还有wouldsooner,hadrather,hadsooner都表示“宁愿”、“宁可”的意思。例如：　IfIhaveachoice,Ihadsoonernotcontinuemystudiesatthisschool.如果有选择的余地，我宁可辍学离开这个学校。　Iwouldratherstayherethangohome.=Iwouldstayhereratherthangohome.我宁愿呆在这儿，而不愿回家。典型例题----Shallwegoskatingorstayathome?----Which___do?　　　　　A.doyourather　　B.wouldyourather　C.willyourather　D.shouldyourather答案B。•Iwouldratheryouputyourheartintoyourstudies。•1）---CouldIborrowyourdictionary?　　---Yes,ofcourse,you____.　　A.might　B.will　C.can　D.should2）---ShallItellJohnaboutit?　　---No,you___.I"vetoldhimalready.　　　A.needn"t　　B.wouldn"t　　C.mustn"t　　D.shouldn"t3）---Don"tforgettocometomybirthdaypartytomorrow.　　---______.　　A.Idon"t　B.　Iwon"t　C.Ican"t　D.Ihaven"t •比较need和dare　这两词既可做实义动词用，又可做情态动词用。作为情态动词，两者都只能用于疑问句，否定句和条件句。need作实义动词时后面的不定式必须带to，而dare作实义动词用时,后面的to时常可以被省略。1）实义动词：need（需要,要求）need+n./todosth/doing2）情态动词：need，只用原形need后加do，否定形式为neednot。例如：　　Needyougoyet?你要走了吗？　　Yes,Imust./No,Ineedn"t.是的，我要走了/不，不急着走。•Dare/darenot•Dareyougooutaloneatnight?•No,Idarenot.•Ididn’tknowwhetheryoudaredsaythattotheteacher.•其他用法•1cannotbutchoose=haveto•Icannotbutchoosetogo.•2cannever..enough/can’t..toomuch•Ican’tthankyoutoomuch.•Youcanneverbecarefulwhencrossingthestreet.专项练习1--Noone_____becomparedwithYaoMinginplayingbasketball.--Oh,youarereallyhisbigfan.AcanBneedCmustDmight2.It____bethepostmanatthedoor.It’sonlysixo’clock.Amustn’tBcan’tCwon’tDneedn’t3.Thepolicestillhaven’tfoundthelostchild,butthey’redoingallthey_____.AcanBmayCmustDshould4.–Ileftmyhandbagonthetrain,butluckilysomeonegaveittoarailwayofficial.--Howunbelievabletogetitback!Imean,someone_____it.AwillhavestolenBmighthavestolenCshouldhavestolenDmusthavestolen5Althoughthis____soundlikeasimpletask,greatcareisneeded.AmustBmayCshallDshould6Ifyou____go,atleastwaituntilthestormisover.AcanBmayCmustDwill7You____parkhere!It’sanemergencyexit.Awouldn’tBneedn’tCcouldn’tDmustn’t8You____buyagift,butyoucanifyouwantto.AmustBmustn’tChavetoDdon’thaveto9Asyouknow,althoughtherearenoclassesonweekendsnow,nostudents_____gooutoftheschoolwithouttheheadmaster’spermission.AwillBmustCmayDshall10They_____havearrivedatlunchtimebuttheirflightwasdelayed. AwillBcanCmustDshould11–Whydidn’tyoucometoSimon’spartylastnight?--Iwantedto,butmymomsimply_____notletmeoutsolatenight.AcouldBmightCwouldDshould12There’snolighton—they____beathome.Acan’tBmustn’tCneedn’tDshouldn’t13–TomcametoworklastFriday,butnoonehasseenhimsince.--_____hehavehadanaccident?AShouldBMustCMightDCould14–ShallIinformhimofthechangeoftheschedulerightnow?--Iamafraidyou____,incasehecomeslateforthemeetingAwillBmustCmayDcan15Liza_____wellnotwanttogoonthetrip---shehatestravelling.AwillBcanCmustDmay16Somepeoplewhodon’tliketotalkmucharenotnecessarilyshy;they____justbequietpeople.AmustBmayCshouldDwould17John,lookatthetime.____youplaythepianoatsuchalatehour?AMustBCan’tCMayDNeed18You_____scoldsuchapupilwhoalwayskeepssilentsoseriouslythatyou____hurthim.Ashould;canBmay;willCmustn’t;mayDcan’t;must19Doctorssaythatexerciseisimportantforhealth,butit_____beregularexercise.AcanBwillCmustDmay20“You_____haveawrongnumber,”shesaid.“There’snooneofthatnamehere.”AneedBcanCmustDwould21We____John’snameontheracelistyesterdaybutforhisrecentinjury.AwillputBwillhaveputCwouldputDwouldhaveput22–MayItakethisbookoutofthereadingroom?--No,you_____.Youreaditinhere.Amightn’tBwon’tCneedn’tDmustn’t23—Whatdoyouthinkwecandoforouragedparents?--You_____doanythingexcepttobewiththemandbeyourself.Adon’thavetoBoughttoCmustn’tDcan’t24.I_____havewatchedthatmovie---it’llgivemehorribledreams.Ashouldn’tBneedn’tCcouldn’tDmustn’t25–Idon’tcarewhatpeoplethink.--Well,you_____.AcouldBwouldCshouldDmight26Myunclewaspoorbutlikedfashion,sohe_____dressupasarichman.AcouldBwouldCshouldDmight27Hemusthavefinishedhishomeworklastnight,_____he?Amustn’tBdidn’tCneedn’tDhasn’t 28Ican’tleave.ShetoldmethatI_____stayhereuntilshecomesback.AcanBmustCwillDmay29Aleft-luggageofficeisaplacewherebags_____beleftforashorttime,especiallyatarailwaystation.AshouldBcanCmustDwill30Thetrafficisheavythesedays.I____arriveabitlate,socouldyousavemeaplace?AcanBmustCneedDmight31There_____beanydifficultypassingtheroadtestsinceyouhavepracticedalotinthedrivingschool.Amustn’tBshan’tCshouldn’tDneedn’t