新人教必修3 Unit1 Grammar情态动词]

情态动词(modalverbs)情态动词主要用来表说话人的看法、意愿、态度等。从用法上来说，它有如下几个特点：1.情态动词本身都有一定的词义；2.情态动词不能单独做谓语；3.情态动词没有人称和数的变化；4.情态动词后接不带to的不定式（除oughtto和usedto外），即接动词原形。一、定义1)Someofuscanusethecomputernow,butwecouldn’tlastyear.2)Thenew-builttheatrecanseat1500people.3)Canthisnewstrue?4)Ithoughwhathesaidcouldnotbetrue.5)Can/CouldIuseyourdictionary?6)Couldyoulendmeahand?1).表能力,常译为“能，会”，could指过去时间。3).表示“请求”“允许”(表请求时，口语中常用could代替can使语气更委婉，回答时用can)2).表示推测，意为“可能”“或许”，用于疑问句或否定句1.can与could二、基本用法4).表示“许可”，可与may换用。Youcangohomenow.5).用于疑问句或否定句或感叹句中时，表猜测、惊讶、不相信等，“可能、能够”。could猜测的可能性更小。Ibelievethathecan'tbesorude.Heisanhonestman,hecouldn'tbetellinglies.6).can’t/couldn’t+have+done不可能表示对过去情况的否定推测Susancan’thavewrittenareportlikethis.7).could+have+done“本应该”表示对过去能做而未做的事情感到惋惜，遗憾It’sapity.Yourclasscouldhavegotthefirstprize.1.Michael____beapoliceman,forhe’smuchtooshort.A.needn’tB.can’tC.shouldD.may2.Mr.Bushisontimeforeverything.How____itbethathewaslatefortheopeningceremony?A.canB.shouldC.mayD.must3.----IstayedatahotelwhileinNewYork.----Oh,didyou?You____withBarbara.A.couldhavestayedB.couldstayC.wouldstayD.musthavestayed4.MysistermethimattheGrandTheateryesterdayafternoon,sohe____yourlecture.A.couldn’thaveattendedB.needn’thaveattendedC.mustn’thaveattendedD.shouldn’thaveattendedBAAA2.can和beableto1)can只有现在时和过去时could，而beableto有更多的时态变化。2)can一般指只身具有的能力，beableto表示经过一段的时间努力后所具有的能力，相当于managetodo或succeedindoing.ThistimeIfailedintheexam,butI'llbeabletopasstheexamnexttime.3)在否定结构中，was/werebeableto和could没有区别。Sheranfastbutshecouldn't/wasn'tabletocatchthebus.3.may与might1).表示“许可”或“请求”，在这样的句中，might比may语气更委婉，客气。肯定回答用may或can，否定回答时用mustn't或can't，表示“不可以”或“禁止”。Eg:---MayIcomein?我可以进来吗？---Yes,youmay/can.可以，请进来。---No,youmustn’t/can't.不，你不能。2).表示可能性，多用于陈述句，否定用maynot表示“可能不”。might比may可能性小。Eg:1)Itmightbetrue.2)Itmaybeatrick.3)Hemaynotcometoday.3).may/mightaswell+动词原形“…还是…的好”Eg:Youmayaswellgoandhavealook.4.用于祈使句表祝愿。Eg:Mayyousucceed!MayGodblessyou!5.mayhavedone和mighthavedone表示对过去的推测。1.SorryI'mlate.I_____haveturnedoffthealarmclockandgonebacktosleepagain.A.mightB.shouldC.canD.will2.Peter_____comewithustonight,butheisn’tverysureyet.A.mustB.mayC.canD.willAB4.will与would1).表“请求、建议”等，用would比用will委婉，客气些Eg:1)Willyoulendmeyourbook?2)Wouldyoulikeacupoftea?2).用于表示意志、意愿和决心。would指过去的意愿和决心。Eg:1)I’llneverdothatagain.2)Theysaidthattheywouldhelpus.3).表示习惯性动作或某种倾向。译作“总是、惯于”would指过去。Eg:1)Fishwilldiewithoutwater.2)Everyevening,shewouldsitbywindow,deepinthought.4).表示功能，译作“能、行”Eg:1)Thatwillbeallright.2)Thisdoorwon’topen.5).用于否定句中，表示“不肯、不乐意”Eg:NomatterwhatIsaid,hewon’tlistentome.5.shall,should,oughtto1).shall用于第一和第三人称，用来征求对方意见或向对方请示。Eg:1)Whatshallwedothisevening？2)Whenshallhebeabletoleavethehospital?2).shall用于二三人称，表示说话人命令、警告、许诺和威胁。Eg:1)Youshallfailifyoudon'tworkhard.2)Heshallbepunished.3).should表示劝告、建议、命令，同义词oughtto；shouldn'thavedone表示不该做却做了。“本不该”Eg:1)Youshouldkeepyourpromise.2)Youshouldn'thavetoldhimthisnews.2)Samsuggestedthatweshouldgoforaswim.4).should和oughtto表示推测、可能，含有按道理应当。Eg:1)Theroadsshouldbelesscrowdedtoday.2)Theyshouldbeathomebynowfortheyhavebeenawayfortwohours.6.can’t用来表示由于特定事实或环境某事肯定不会发生。Eg:1)---Listen,someoneisknockingatthedoor,whocanitbe?---Itcan’tbeTom,hehasgoneabroad.2)---Can/couldtheyhavefinishedthework?---No,theycan’thavefinishedtheworksosoon.7.must1).表示义务或强烈的劝告，意为“必须”“应该”，其否定式表示“不应该”“不许可”“不准”“禁止”。Eg:1)Youmustfinishyourhomeworkfirst.2)Childrenmustn’tspeaklikethattotheirparents.2).回答must所在的一般疑问句时，否定回答用“needn’t”或“don’thaveto”.Eg:---Mustwefinishtheworktomorrow?---No,youneedn’t/don’thaveto,butyoumustfinishitinthreedays.3).表推测，用于肯定句，意为“一定”“务必”。Eg:1)Bettymustbeinthenextroom.2)Hemustbewateringtheflowersinhisgarden.4)must表示发生了某种与说话人的愿望相反，不受欢迎的事，意思是“偏偏，偏要”。eg.WhyitmustrainonSunday?怎么偏偏是星期天下雨？Whymusthedoitthatway?为什么他偏要那样做？情态动词+havedone这是历年高考热点之一，可表示“推测、责备、怀疑”等多种意义。一、表示对过去事情的推测或估计1.musthavedone“想必或肯定已经做了某事”eg:Thegroundisratherwet,soitmusthaverainedlastnight.2.may/mighthavedone“可能/大概已经做了某事”eg:Tommayhavegonetoshanghai,butIstillnotsureaboutit.3.can’t/couldn’thavedone“不可能已经做了某事”eg:Thegroundisverydry,soitcan’thaverainedlastnight注：在疑问句中can/could表示对过去情况的疑问性推测，“可能已经…了吗？”eg:Someonemusthavebrokenintoourbedroom,Whocouldhavedoneit?二、表示对过去所发生事情的遗憾或责备1.should/oughttohavedone“过去本该做而没做”eg:IreallyregrettedwastingthehourswhenIshouldhavestudiedhard,butitwastoolate.2.shouldn’t/oughtn’ttohavedone“过去不该做的事却做了”eg:I’mverysorryforthewordsIshouldn’thavesaidtoyouatthatmoment.3.could/mighthavedone“本来能够做的事却没做”eg:Hecouldhaveworkedouttheproblem.Heneedn’thavecome.Hedidn’tneedtocome.他本没有必要来（实际也没来）他本没有必要来（实际却来了）4.needn’thavedone“原本不必做的事却做了”eg:Yourhomeisnotfarfromyourschool,soyouneedn’thaveleftinsuchahurry.5.didn’tneedtodo/didn’thavetodo“没有必要做，实际也没做”eg:Ididn’tneedtocleanthewindows.Mysisterdidit.6.Wouldratherhavedone“本想做却未做成”eg:IwouldratherhavecometohelpyouwithyourEnglish,butIwastoobusyatthattime.