语法专项5情态动词和助动词【情态动词综述】情态动词是一种本身有一定的词义,但要与动词原形及其被动语态一起使用,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。情态动词后面加动词原形。情态动词没有人称或数的变化,但部分情态动词有 时态的变化。情态动词的否定形式,直接在情态动词后加not。情态动词有四类:①只做情态动词:must,can(could),ma y(might)……②可作情态动词又可作实义动词:need,dare③具有情态动词特征:have(had,has)to,u sedto④情态动词表猜测:一肯一否三不定(must一肯,mustnot一否,can,could,would三不定。)注:m ustn''t代表强烈禁止。can的用法及意义(1)表泛指情况下的“能力”。Wecanoperatecomputera ndtheycandriveacar.我们能操纵电脑而他们能开车。(2)口语、非正式场合表“许可”。Nowyou cango.现在你可以走了。(3)疑问、否定句中表“可能性”。Canhebewellabovefifty?He lookssolively.可能他50多岁了?可他看上去却如此有活力。(4)机会不多的“可能”。Somethingsi nthehomecanbedangerous,especiallyifyouhaveyoungchildre n.家中的一些东西可能很危险,尤其是家里有小孩子。could的用法could有两个方面的用法:其一是can的过去式,其二 用在口语或对话中,表示语气比can更委婉。用作第二种意义时,即使用could表疑问仍用can作答。CouldIuse yourbikeforawhile?我能用一下你的自行车吗?Yes,youcan.可以。beableto的 用法beableto表“能够、可能”时,可用在各种时态中,尤其是在表达具体某次能力时,应用beableto而不用 can。不过beableto后不得用被动语态。Ifyoucanfinishyourhomeworkintim e,I’llbeabletoallowyoutowatchTV.如果你按时完成作业,我可以让你看电视。may的 用法(1)正式场合的“许可”“允许”,表示“不许、不允许”时,用mustnot/mustn’t而不用maynot。S inceyouhavedoneyourwork,youmayhavearest.既然你干完活了,就休息一下吧 。MayIwatchTVafterdinner?晚饭后,我可以看电视吗?Yes,youmay.可以。No,yo umustn''t.绝对不行。(2)用在肯定或否定句中表“可能性”。Yourmummaycometoseeyou tomorrow.明天你妈妈可能来看你。(3)(用在比较正规场合或书面语中)表祝愿:Mayyoubehappyforev er!祝你永远幸福。might的用法might是may的过去式,但在以下两种情况下表示语气的更加委婉或表示看法时更加不肯 定。MightIuseyourcomputer?我能用一下你的电脑吗?may/mightaswelldosth. 是一固定短语,意为“还是做……为好,不妨做……”。Bytheway,youmay/mightaswellcome hereearlier.顺便问一下,你最好早来这儿。must的用法:(1)肯定句中,意为“必须,应该”侧重主观上的看法,否定 句中(mustnot/mustn’t)意为:“不许、不准、严禁、禁止”。Everycitizenmustobeythe rules.每一个公民必须守法。(2)表推测时,只有用在肯定句中,意为“一定,肯定……”Aftersuchalongwa lk,youmustbetirednow.走了这么长的路,你现在一定累了。(3)表示发生了某种与说话人愿望相反,不受 欢迎的事,意为“偏偏、偏巧”。WhymustJamesdoitinthatway?为什么吉姆偏偏那样做呢?have to的用法:haveto意为“必须,应该,不得不,只好”,侧重客观需要。haveto可用在各种时态中,肯定句后面接动词 原形,但它有人称和数的变化,变否定句和疑问句时,必须接助动词do/does或did。It’sgettinglate.I havetogohomenow.太晚了,现在我必须回家了。注意:nothaveto=needn’t,意为“不必” 。—MustIgiveittoTomimmediately?我必须立刻把它还给汤姆吗?—No,youdon’ thaveto./—No,youneedn’t.Youmaydothattomorrowmorning.不必 了。你可以明天上午还给他。can/may/must表推测意义时的用法表示对现在或将来情况的推测时,用can/may/must +动词原形结构。表示对过去情况的推测时,用can/may/must+havedone…结构。在推测性句子中,can/ma y/must不参与反意疑问。反意疑问的谓语与can/may/must后的谓语动词保持相应一致。can/may/must表推 测意义时,必须用在规定的句式中(见下表):句式肯定句·意义否定句·意义疑问句·意义can×can''t…不可能can…可能吗?m aymay…可能,也许maynot…可能不×mustmust…一定,肯定××Howdoyouknowabouti t?Shemusthavetoldittoyou.你怎么知道的?她一定告诉你了。should的用法(1)在提出建议 ,表示劝告时多译为“应该”。Weshouldkeepourpromises.我们应该信守诺言。(2)表示一种估计的情况, 按平常或正常的情况推断时译为“估计……,按理应该……”用作此义时,可用oughtto代替。Yourworksshould bepublishedinamonthatmost.你的作品估计最早一个月内能印刷。(3)用在条件状语从句中表极 小的可能性时译为“万一……”。Itisnotlikelytohappen,butifitshould,wen eedtobewell-prepared.这个事情不大可能发生,但是万一发生,我们需要做好准备。(4)与havedone …连用,表示与过去事实相反并含有明显的抱怨责备(他人或自己)意义时,译为“本来应该、本该……(而事实却没有)”。用作此义时,可用 oughtto代替。Theflowerisdead.Ishouldhavewatereditmoreof ten.花儿死了。我本该勤浇一浇。(5)用在与将来事实相反的虚拟语气的从句中(从句中的should不可省略)。Ifits houldrain,whatwouldwedo?如果下雨,我们怎么办呢?=Shoulditrain,what wouldwedo?(6)在Itis(high/about)timethat+主语++其它结构中可用shoul d(但should不可省略)。Itis(high)timethatweshouldgetup.到了我们起床的 时间了。(7)含有条件的虚拟语气中,如果主句的主语是第一人称I或we时可用should。IfIwereyou,I shouldn’tdothat.如果我是你,我不会那样做。(8)在“Itisnecessary/important/n atural/strange/curious…that+主语+(should)+动词原形+其它”这类主语从句中,必须用sh ould且should可以省略(但主语后必须接动词原形)。Itisnecessarythateveryone(sh ould)masteraforeignlanguage.每个人掌握一门外语是有必要的。(9)在insist(坚持)、or der/command(命令)、suggest/propose/advise(建议)、demand/request/require /ask(要求)等动词后的宾语从句中,或这些动词的过去分词用在“Itis/was+该类动词的过去分词+that+主语+( should)+动词原形+其它”主语从句中或这些动词的名词用在表语从句或同位语从句中,从句的主语后必须用should+动词原 形(should可以省略,但主语后仍须用动词原形)。Ourteacherorderedthatwe(should)ha ndinourexercisesbeforeclass.我们的老师要求我们课前上交练习。should与ought to的区别(1)oughtto除在表达“按理应该、估计……”和“本来应该,本该……(而事实上却没有)”两种情况下能代替sho uld外,它也可以表示建议或劝告,但oughtto更侧重义务或责任或表示更容易做的事,也译为“理应,应该,必须”。You oughttobehungrybynow?到现在,我估计你饿了吧?Ioughttohavefollowedy ouradvice.我本该听从你的建议。(2)oughtto的反意问句,多用should/shouldn’t(有时也可用 ought/oughtn’t)+主语。Astudentoughttofinishexercisesontime, shouldn’t(oughtn’t)he?一个学生应该按时完成作业,不是吗?shall的用法:(1)在疑问句中,用于第 一、第三人称,用来征询对方意见或请求指示。Mr.Smithwantstoseeyou,manager.Shallh ewaitoutsideorintheoffice?经理,史密斯先生想见你,让他在外边等还是在办公室等?(2)用在第 二、第三人称之后表示说话人的“许诺、警告、命令、威胁”等意愿。Youshallhavethestory-bookass oonasIfinishreadingit.我已读完这本故事书,我就给你。(3)用在Let’sdosth.的 反意疑问句中。Let’sgoswimming,shallwe?我们去游泳吧,怎么样?注意:Let’snotdost h.的反意问句,常用allright或OK?It’sraininghard.Let’snotgoout,a llright(OK)?外面雨下的很大。我们不出去了吧?will的用法:(1)在疑问句中,用于第二人称,用来征询对方意见或 请求指示。Willyoupleasedosomeshoppingwithme?你能陪我去购物吗?(2)用在各人称 中,表示“意愿、愿意”。Comeon,children.Iwilltellyouallaboutmystory .孩子们,快点。我要告诉你们我的故事。(3)用于各人称,表习惯性或规律性,意为“总是、惯于”。Manwilldie.人总 是要死的。(4)用在Letusdosth.或否定祈使句Don’tdosth.后的反意疑问句中。Letuss tartnow,willyou?我们现在开始,好吗?Don''tshutthedoor,willyou?不要关门 ,好吗?(5)will的否定式(won’t)还可表示某东西总是或老是有不妙的情况发生。Thedoorwon’tclose .门老是不关。would的用法:(1)是will的过去式,表示过去时间的意愿,用于各人称。Shesaidthats hewouldcomeandhelpus.她说要过来帮助我们。(2)用于第二人称,表示更客气,更委婉地征询对方意见或 请求指示。Wouldyoulikesomemoremilk?喝点牛奶?Yes,please.好的,谢谢。(3)I wouldliketo简略式为I’dliketo表示说话者客气、委婉的意愿要求。I’dliketohave alookatyournewbicycle.我看看你的新自行车。(4)would表示过去时间“总是、惯于”的习惯动 作。Theoldladywouldsitatthedoorlikethatafewhours.这个老人总 是坐在门口好几个小时。usedto的用法:usedto与would一样,可以表示“过去总是,过去常常”的意义,但在下列 情况下,只能用usedto而不用would。(1)当后面接的是情感动词时或意向动词时。Iusedtolikeme atandIlikefishnow.我过去总是喜欢肉,而现在喜欢鱼。(2)当后面接表状态的动词或be动词时。Th eSmithsusedtoliveinthecountry.史密斯夫妇过去住在乡下。(3)强调过去与现在的对比或 无具体的上下文且又无具体的时间状语时。Tomusedtolikemaths.However,helikesChin esenow.汤姆过去喜欢数学,然而现在喜欢语文。(4)与be或get连用,表示“习惯于……”意义时,(be/get usedto用作此意时)其后必须接名词、代词、动名词,切不可接动词原形。Ihavebeenlivinginthe countrysideforovertenyears,soIhavebeenusedtothiskind ofquietness.我已经在乡下住了十多年了,因此我已经习惯了那里的安静。hadbetter与wouldrathe r的区别这两个短语,意义不同,但用法相近,它们均有以下三种用法:(1)这两个短语与其它所有情态动词一样——后接动词原形:Youh adbetterstayathome,doingyourhomeworkinsuchbadweather.在 这样恶劣的天气里,你最好在家里做作业。(2)这两个短语的否定式均是在固定结构之后加not:Youhadbetternot makesomuchnoise.Thebabyisasleep.你最好不要能出这么大的噪音。小宝宝睡了。(3)这两个 短语的疑问式或反意疑问式都不必接助动词:HadIbetterstayhere?IfIshouldgo,would Ibepunished?我能呆在这儿吗?如果我去,会不会受到惩罚。但wouldrather还可与than或pr eferto连用,构成搭配:wouldratherdosth.thandosth.=woulddosth. ratherthandosth.=prefertodosth.ratherthandosth.宁愿做(前面) 某事而不愿做(后面)某事:LiuHulanwouldratherdieforrevolutionthanlive bykneeling.刘胡兰宁愿为革命而牺牲也不屈膝苟活。wouldrather后直接接动词原形;但wouldrathe r后接句子时,常用过去式,过去完成时或should+动词原形等结构形式。Iwouldratheryoucameto morrow.我愿意你明天来。dare与need用法区别这两个词既是实义动词,又可作情态动词用,但用作情态动词时,只能用在 否定句,疑问句或条件状语从句中,(肯定句中,不能用作情态动词,只用作实义动词)。dare情态动词的用法:Idarenotd othat,orI’llbebeatenbymyfather.我不敢那样做,否则我父亲会打我。dare实义动词 的用法:肯定句中,常用daretodosth.结构;否定句中,常用…notdare(to)dosth.结构(否 定句中的不定式符号to可以省略)。Itistimethatweshoulddaretohaveatry.你 敢穿过那片森林吗?Dareyougothroughthewoods?他不敢向爸爸要零花钱。Hedarenotas khisfatherforpocketmoney.Hedarednotaskhisfatherforpoc ketmoney.Hedidn’tdare(to)askhisfatherforpocketmoney.He doesn’tdare(to)askhisfatherforpocketmoney.他不敢向他父亲要零花钱。ne ed情态动词的用法——(用在否定,疑问或条件从句中)Youneedn’tgoandtellheraboutit. Tomhastoldher.你没有必要去告诉他。汤姆已经跟她说了。need实义动词的用法:(1)作“需要”讲,后接名 词或代词。Ibadlyneedahaircutnow.现在我急需理发了。(2)作“需要”讲,后接动名词的主动式或动词 不定式的被动式。Thelittlechildneedstobeoperatedonatonce.这个小孩需要 立刻手术。(3)作“需要”讲,后接复合结构。Doctor,Ineedmybadtoothout.医生,给我把牙拔了 吧。(4)作“需要”讲,后接不定式。TomorrowisSunday.Youdon’tneedtoarrivee arly.明天是周日,我们没有必要早去。附:need用作名词时,用inneed(of…)结构。Afriendin needisafriendindeed.【助动词综述】助动词本身没有词义,不可单独使用。主要是是用来帮助主要动词构成各种时 态,语态,语气以及否定或疑问结构的动词。基本助动词基本助动词只有三个:be,do,have,他们没有词汇意义,只有语法作用,如 协助构成进行体,完成体,被动态,否定句,疑问句等。助动词be的用法1.be+现在分词,构成进行时态,例如:Theyare havingameetinginthehall.他们正在会堂开会。Englishisbecomingmorea ndmoreimportantnow.现在英语越来越重要。2.be+过去分词,构成被动语态,例如:Thewindow isbrokenbyTom.窗户是汤姆打碎的。Englishistaughtallovertheworld. 世界各地都在教英语。3.be+动词不定式,可以表示以下内容:表示最近、未来的计划或安排。例如:Heistogoto NewYorknextweek.他下周要去纽约。Wearetoteachthefreshmenthister m.这个学期,我们要教新生。表示命令。例如:Youaretoexplainthis.对此你要做出解释。Heisto cometotheofficethisafternoon.要他今天下午来办公室。征求意见。例如:HowamIt oanswerhim?我该怎样答复他?Whoistogothere?谁该去那儿呢?表示相约、商定。例如:Wear etomeetattheschoolgateatseventomorrowmorning.我们明天早晨7点在 校门口集合。助动词have的用法1.have+过去分词,构成完成时态,例如:JackhasleftforLondo n.杰克已经去了伦敦。Bytheendoflastmonth,theyhadfinishedhalfoft heirwork.到上月末,他们已完成了一半的工作。2.have+been+现在分词,构成完成进行时。例如:Ihav ebeenstudyingEnglishfortwentyyears.我一直在学英语,已达二十年之久。3.have +been+过去分词,构成完成时的被动语态。例如:EnglishhasbeentaughtinChinafor manyyears.在中国,英语已经学习很多年了。助动词do的用法1.构成一般疑问句。例如:Doyouwantto passtheCET?你想通过大学英语测试吗?DidyoustudyGerman?你们学过德语吗?2.do+n ot构成否定句。例如:Idonotwanttobecriticized.我不想挨批评。Hedoesn’tli ketostudyatschool.他在学校里不想学习。Inthepast,manystudentsdidn otknowtheimportanceofEnglish.过去,好多学生不知道英语的重要性。3.构成否定祈使句。例如: Don’tgothereatnight.晚上不要去那儿。Don’tbesoabsent-mindedincla ss.在课堂上不要这么心不在焉。【温馨提示】构成否定祈使句只用do,不用did和does。4.放在动词原形前,用来加强动词的语气 。例如:Docometomybirthdaypartytonight.今晚一定来参加我的生日宴会。Ididgo thereyesterday.昨天我确实去那儿了。Marydoesmissyouverymuch.玛丽确实很想念你 。5.用于倒装句。例如:NeverdidIhearofsuchathing.我从未听说过这件事。Onlywhe nwebeginourcollegelifedowerealizetheimportanceofEngli sh.进了大学后,我们才意识到英语的重要性。6.用作代动词。例如:----DoyoulikeBeijing?--你 喜欢北京吗?----Yes,Ido.--是的,喜欢。(do用作代动词,代替likeBeijing.)Heknows howtodriveacar,doesn''the?他知道如何开车,对吧?【小试牛刀】I用适当的情态动词填空1. –Mustwegobackatonce?–No,you_______.2.Mydaughterwasil l.I_____takecareofher.3.You’dbettergotoyourhometown, _____you?4.Yourshoesaresodirty._____Iwashthemforyou? 5.Jackstartedearly.He______inthecitynow.6.We______us ethenewlabearlynextyear.7.Tim_____giveuphisworkbecau sehewasbadlyillinhospital.8.______watchTVnow?NO,you mustn’t.9.We_____wasteoursparetimeatschool.10._____you tellusifitsnowsinwinterinChumming?Keys:1.needn’t2.ha dto3.hadn’t4.Shall5.mustbe6.should7.hadto8.May/ Can9.mustn’t10.CanII用适当的be动词或助动词填空。1.?Every?student?_______ ?got?a?book.?2.?The?number?of?students?in?the?school?_______?now? rising.??3.?A?number?of?boys?_______?playing?basketball?at?the?mo ment.??4.?There?_______?something?else?in?the?desk.??5.?Tom,?toge ther?with?his?mother,?_______?gone?to?New?York.??6.?The?teacher?w ith?two?students?_______?playing?sports.?7.?This?pair?of?trousers ?_______?made?by?my?aunt?last?year.?8.?Five?months?_______?a?long ?time?to?wait.??9.?Here?_______?some?books.?10.?To?clean?the?room ?_______?your?dutyKeys:1.has2.is3.are4.is5.has6.is7. was8.is9.are10.isⅢ用所给词的适当形式填空。1.Ithoughtyou_____(may) likesomethingtoread,soIhavebroughtyousomebooks.2.Where ismypen?I____(must)havelostit.3.Ididn’thearthephone .I___(mustbe)asleep.4.---Therewerealreadyfivepeopleinth ecar,buttheymanagedtotakemeaswell.----It____(can’tb e)acomfortablejourney.5.It’snearlyseveno’clock.Jack___(s hall)behereatanymoment.6.Thatbigcinema______(can)seat2,0 00people.7.—CouldIborrowyourdictionary?—Yes,ofcours eyou_______(could).8.—MightIwatchTVaftersupper?—Yes, you________(might).9.--Willyoustayforlunch?--Sorry,I__ ___(can).Mybrotheriscomingtoseeme.10.--MayIpickaflowe rinthegarden?--No,you________(must).Putonmoreclothes. You________(must)befeelingcoldwithonlyashirton.12."Must Idrivetohishouseandpickupthechildren?""No,you________ (need)."13.Thereissomeoneknockingatthedoor.________(Cou ld)itbeTom?14.Twoyearsago,myhusbandboughtmeabicycle.I fyouliveintown,itisoftenfasterthanacarandyou_______ _(nothaveto)worryaboutparking.15.--IsJohncomingbytrain? --Heshould,buthe____(may)not.Helikesdrivinghiscar.16.- -Iheardtheywentskiinginthemountainslastwinter.--It____ (cannotbe)truebecausetherewaslittlesnowthere.17.–MayI sitbesideyou,sir?---No,you______(can).Mygirlfriendisco mingsoon.--__(May)IspeaktoMary,please?--Sorry,she__(can )cometothephonebecausesheisn’tin.19.---Iwanttoknowi fI____(might)smokehere.---No,you____(must).Couldyousee thesign“NOSMOKING”there?20.Mywifeneverremembersmyteleph onenumber.Shealways____(haveto)lookitup.21.---____(Can) youpassmetheEnglishmagazine,please?---Sure.Hereyouare .22.---MustIgotoworkwithyou?---No,you_____(need).Lind a______(may)gowithme.23.---__(Shall)ItellMarythetestr esults?---No,you____(need).She’salreadygotthescore.You__ __(oughtto)becarefulwhencrossinghere.Thetrafficlightsar en’tworking.25.---CouldIborrowyourbicycle?---Yes,ofcou rseyou_____(could).26.Joan_____(may)comewithusthisafternoo n,butsheisn’tverysureyet.I_____(dare)askyouthequestion becauseIthinkI_____(must)bewrong.28.---Whatdoyouthinko fthisanswer?---Idon’tthinkit____(could)beright.29.Whe nweworkedinthesameoffice,we_____(will)oftenhavecoffee together.30.Hedoesn’thavetoworktomorrow,butyouhavegott o,____(have)you?31.---MayIsmokehere?---Ifyou___(must),c hooseaseatinthesmokingsection.32.---Icameherebytaxian dthedriverchargedme50yuan.---Really?You_____(shall)have comebybus.Keys:mightmustmusthavebeencouldn’thavebeenshou ldcancanmaycan’tmustn’tmustneedn''tcan?don''thavetomaycould n’tbecan’tMay;can’tmay;mustn’thastoCouldneedn’t;mayShall; needn’toughttocanmaydaren’t;mustcanwouldhaven’tmustshouldⅣ单句改 错1.---DoyoustillrememberwhenwewenttotheGreatWall?--- Ican’trememberitwell,butcanithavebeensometimelastMay ?---IwonderwhyMr.Lindidn’tcometowork.---Heshouldhave beenill.3.---Noonepassedthemathematicsexaminationtoday.- --Iguessweshouldreviewtheexerciselastnight.4.Sheshouldn’ tleavethehospitalsosoon,forshehasn’tyetrecovered.Whydi dn’tyoutellmetherewasnomeetingtoday?Ineedn’tdriveallthewayherethroughtheheavysnow.6.Thebookisneitheryoursnormine.Whosebookcoulditbe?7.Itissurprisingthatheshallhavebeensofoolish.8.Itmusthaverainedlastnight,mustn’tit?9.Michaelneedn’tbeapoliceman,forhe’smuchtooshort.10.–IstayedatahotelwhileinNewYork.--Oh,didyou?YoucanstaywithBarbara.11.IfIcangowithyou,Iwouldfeelveryglad.12.Therewasalotoffunatyesterday’sparty.Yououghttocome,butwhydidn’tyou?13.Sinceyouhavemadesuchgoodpreparations,therecouldn’tbeanyproblemaboutpassingthecomingexam.14.Sorry,I’mlate.Imayhaveturnedoffthealarmclockandgonebacktosleepagain.15.IfIhadtime,Imaygowithyou.Keys:将can改为could将should改为might将shouldreview改为shouldhavereviewed将shouldn’tleave改为shouldn’thaveleft将needn’tdrive改为needn’thavedriven将could改为can将shall改为should将mustn’t改为didn’t将needn’t改为can’t将canstay改为couldhavestayed将can改为could将oughttocome改为oughttohavecome将couldn’t改为shouldn’t将may改为might将may改为might |
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