【专题六】情态动词和虚拟语气
【考点分析】
情态动词
1.考查情态动词的基本用法
①shall用于一、三人称疑问句表示征求对方意见;用于二、三人称陈述句表示说话人给对方的命令、警告、允诺或威胁等;may表示“允许、可以”,语气比较委婉。
②must用于疑问句,表示责备、抱怨的感情色彩,意思为“偏偏,偏要”,mustn’t表示禁止,是说话人强有力的劝告。cannot表示“不可能”;neednot表示“不必要”;maynot表示“可能不,可以不”。
③needn’t表示“没有必要”
④would表示过去反复发生的动作或某种倾向
⑤表示经过努力而成功的某一次动作,只能用was/wereableto,而不能用could;could还可以表示过去的某种能力
⑥考查情态动词用作答语的情况
2.考查情态动词+动词不定式一般式表推测的用法
①肯定的推测一般用must,should,may(might)或could(不用can),其中,must的语气最强,译为“肯定”、should的语气次之,译为“很可能”、“应该”;按常理推测的may(might),could语气最弱,译为“也许”。
②否定的推测:语气不很肯定时,常用maynot,mightnot或couldnot,译为“可能不”“也许不”;否定语气较强时,则用can’t,译为“根本不可能”、“想必不会”,表示惊异、怀疑的感情色彩
③疑问句中推测往往用can或could
3.考查情态动词+动词不定式的完成式表推测的用法
4.考查情态动词+动词不定式完成式的其他用法
①should(oughtto)+不定式的完成式:本来应该做而实际上又没有做。其否定形式表示某中行为不该发生却发生了。
②needn’t+不定式的完成式:本来不必要做的而实际上又做了
③could+不定式的完成式:本可以做而实际上未能做,含有遗憾的意味
虚拟语气
1.虚拟条件句的基本结构及其用法
①与现在事实相反的虚拟条件句
②与过去事实相反的虚拟条件句
③与将来事实相反的虚拟条件句
2.虚拟语气的活用
①时间错综虚拟结构
②省略if的虚拟结构
③并列连词或副词暗示的虚拟结构
④介词或介词短语暗示的虚拟结构
⑤asif/asthough方式状语从句中的虚拟语气
⑥名词性从句中的虚拟语气
⑦分词短语暗示的虚拟结构
⑧上下文语境中的虚拟结构
【知识点归纳】
i.情态动词
1.表示“能力、许可”的can/may
①表示能力的情态动词用can/could
acomputer_____thinkforitself,itmustbetoldwhattodo.
a.can’t b.couldn’t c.maynot d.mightnot
②表示许可时用may/might,can/could都可以,但在问句中用could…?
或might…?以使口气委婉客气,其回答一定要用can或may,以使回答口气明确(must表示一
定,必须,mustn’t表示禁止,不许可)
—couldicallyou byyourfirstname? —yes,you______
a.will b.could c.may d.might共
johnny,you_____playwiththeknife,you_____hurtyourself.
a. won’t/can’t b.mustn’t/may c.shouldn’t/must d.can’t/shouldn’t
③在肯定句中could不可以用来表示过去某一特定场合的能力,而要用was/wereableto。
如不可以说:theycouldjumpintotheseabeforetheboatwasblownup
而要说:theywereableto/managedtojumpinto…
thefirespreadthroughthehotelveryquicklybuteveryone_____getout.
a.hadto b.would c.could d.wasableto
但在否定句中could/was(were)ableto可以通用:
icouldn’t/wasn’tabletoseehimyeaterday.
④表示许可时用may/can都可以。只不过用may时较侧重讲话人的许可,而can较侧重客观情况的许可,must则表示必须做某事。
2.表示“推断、判断”的can,may,must
①在肯定句中都可以用来表示可能。在含义上must语气最为肯定,may表示的是事实上的可能性:
peter______comewithustonight,butheisn’tverysureyet.
a.must b.may c.can d.will
而can表示的是逻辑上的可能性:maryisinpoorhealth.shecanbeillatanytimes.
②在否定句中只能用can和may。此时can’t用以代替mustn’t,语气比maynot更强。can’t中文可以翻译为“不可能”、maynot中文可以翻译为“可能不”。
michael______beapoliceman,forhe’smuchtooshort.
a.needn’t b.can’t c.should d.may
③在疑问句只能用can,不能用may和must
hemaybeverybusynow.
canhebeverybusynow?
hemustbeverybusynow.
canhebeverybusynow?
3.表示“请求、提议”(用在疑问句中)的can和could,这时could比can语气更婉转
can(could)yougivemealifttothestation?
你(您)能不能让我搭你(您)的车去车站呀?
4.表示“惊讶、怀疑”(用在疑问句中)的can和could,这时could比can语气更婉转
whocanitbeatthistimeofday?这个时候到底会是谁呢?
5.构成下列特殊句式的can
①cannot/cannever…too…cannot…enough“无论怎么……也不为过分,越……越好,非常……”
sinceitisagoodthing,wecannotdoittoosoon.
既然是好事情,我们越早开始做越好。
②can’thelpdoing…,cannothelpbutdo…,cannotbutdo…“禁不住,不由得,不得不”共
icannothelpadmiringthepicturewheneverilookatit.每当我看到这幅画时,我都禁不住要鉴赏它。
whenaclosefrienddies,youcannotbutfeelsad.
亲密的朋友去世时,你会不由得感到悲伤。
6.表示祝愿、祝福的may,此时句子用倒装语序
mayhelivetoanoldage!愿他长命百岁!
maygodbewithyou!愿上帝保佑你!
7.shall/should
用于人称 意义
shall 第一、三人称 征求对方的意见
第二、三人称 说话人给对方的警告、命令、允诺、威胁
用于法律、法规等条文中 应……,须……,得……
whatshallwedothisevening?
注意:may用于征求对方的许可,而shall用于征求对方的意见或指示:
mayihavealook?我能看一看吗?
shallihavealook?需要我看一看吗?
youshallfailifyoudon’tworkharder.(警告)
heshallhavethebookwhenifinishreading.(允诺)
heshallbepunished.(威胁)
thefineshallbegivenincash.罚款须以现金缴纳。
should 意义
①(表义务、责任的)应该
②(表预期的)应该会,想必会,一定……会把
③(表惊讶、遗憾的)竟然、居然
④(与疑问词连用,表意外、惊讶、纳闷等的)究竟是,到底
⑤(用于表示命令、建议、请求等词后面的that从句中,且should可以省略)应该,必须
①youshouldapologizetohim.
②thephotosshouldbereadyby12:00.
③i’msurprisedthatyoushouldspeakinsuchaway.
④whoshouldccomeinbutmyoldfriendbetty.我当究竟是谁进来了呢,原来是我的老朋友贝蒂呀。
⑤isuggestedthathe(should)changehismind.
mysuggestionwasthathe(should)changehismind.
注意:oughtto表示“应该”(与should同义,只是语气稍重一些),也可表示推测。
yououghttotakecareofhim.
heoughttobehomebynow.
8.will/would
①请求、建议,would比will委婉客气
wouldyoupassmethebook?
②表示意志、愿望和决心
iwillneverdothatagain.
theyaskedusifwewoulddothatagain
③可表示过去反复发生的动作或某种倾向
duringthevacationhewouldvisitmeeveryweek
thewoundwouldnotheal.
④表示估计或猜想
itwouldbeabouttenwhenhelefthome.
whatwouldshebedoingthere?
9.dare和need
①need作为情态动词只有一种形式,只用于否定句和疑问句。
②dare作为情态动词用时有两中形式:dare和dared两个词形。
除了可以用于否定句和疑问句外,还可以用于条件从句或表示怀疑的句子中。
ifhedarecome,iwillkickhimout.
idon’tknowwhetherhedaresay.
note:hedoesn’tdare(to)answerthequestion.
doesshedare(to)enterthedarkroom?共
10.情态动词+havedone的用法
①could+havedone:本可以做而实际上未能做
youcouldhavedonebetter,butyoudidn’ttryyourbest.
②cannot+havedone:表示对过去行为的否定推测
hecannothavebeentothattown.
③can+主语+havedone:表示对过去行为的怀疑或不肯定
canhehavegotthebook?
④might(may)+havedone:对过去发生的行为不太肯定的推测
hemaynothavefinishedthework.
ifwehadtakentheotherroad,wemighthavearrivedearlier.
(mood:might>may,possibility:might<may)
⑤must+havedone:对过去发生的行为肯定的推测。其否定式为:cannothavedone
youmusthaveseenthefilm.
youcannothaveseenthefilm.
⑥needn’t+havedone:本来不必要做的而实际上又做了
youneedn’thavewateredtheflowers,foritisgoingtorain.
注意:didn’tneedto(haveto)do:没有必要做而实际上也没有做
ididn’tneedtocleanthewindows.mysisterdidit2hoursago.
⑦should(oughtto)+havedone:本来应该做而实际上又没有做。
其否定形式表示某种行为不该发生却发生了。
youshouldhavestartedearlier,butyoudidn’t.
sheshouldn’thavetakenawaymymeasuringtape,foriwantedtouseit.
注意:本结构还可以表“推测”的意思
heshouldhavefinishedtheworkbynow.
到现在他应该已经做完那项工作了。
11.其它情态动词
①haveto
haveto表示“必须,不得不”,在这个意义上与must很接近,但must表示的是说话人的主观看法,而
haveto表示的却是客观需要.haveto比must有更多的形式。
thetvsetisbroken.ihavetobuyanewone.
thestudentswillhavetoknowhowtousethecomputers.
注意:在回答must的问句时,否定式常用neednot(needn’t)或don’thaveto表示“不必”。而不用
mustnot,因为mustnot表示“不可以”。
②usedto
表示过去的习惯动作或状态(现在已不复如此)
—didyouusetogotheretoseeyourbrother?/usedyoutogotheretoseeyourbrother?
—yes,idid(usedto)./no,ididn’t(usedn’t).
注意:would也可表示过去反复发生的动作或某种倾向,但是不涉及到现在。
③hadbetter
表示“最好(做……)”
wehadbettergonow.
其否定式为hadbetternot
ii.虚拟语气
(一)一般虚拟结构
类别 用法 例句
if引导的条件从句 与现在事实相反 从句动词:过去式(be用were)
主句动词:should/would/could/might+动词原形 ifhewerehere,hewouldhelpus.
与过去事实相反 从句动词:had+过去分词
主句动词:should/would/could/might+have+过去分词 ifihadbeenfree,iwouldhavevisitedyou.
与将来事实相反 从句动词:过去式/should+动词原形/were+不定式共
主句动词:should/would/could/might+动词原形 ifitshouldraintomorrow,wewouldnotgocamping.
注意:主句中的should只用于i、we,但在美国英语中,should常被would代替;从句中的should可用于各种人称,且不可以被would所代替。
(二)混合虚拟结构
1.不同时间的虚拟
ifhehadlistenedtome,hewouldnotbeintroublenow.(从句与过去事实相反,主句与现在事实相反)
ifhehadtoldmeyesterday,ishouldknowwhattodonow.(从句与过去事实相反,主句与现在事实相反)
ifiwereyou,iwouldhavegonetoherbirthdayparty.(从句与现在事实相反,主句与过去事实相反)
ifyouhadn’tlentmesomemoney,icouldn’thaveboughtthenewhouseandmostlikelyiwouldbestilllivinginthedangeroushousenow.(从句与过去事实相反,and后面的主句与现在事实相反)
2.虚拟与陈述的混合
hecouldhavepassedtheexam,buthewasn’tcarefulenough.
youshouldhavecomeearlier.thebusleftamomentago.
(三)特殊句式虚拟结构
1.省略连词if。在书面语中,如果虚拟条件从句中有were,had或should,可以把if省略,把这几个词放到主语之前,构成主谓倒装。
shouldhecome(ifheshouldcome),tellhimtoringmeup.他要是来了,让他给我打个电话。
wereiyou(ifiwereyou),iwouldnotdoit.我要是你,就不做这事。
2.suggest,order,propose,request,require,demand,advise,insist+宾语从句(should)do
hesuggestedthatwe(should)savemoneyforthefuture.
theundergraduateinsistedthathe(should)gotoworkinthesouth.
注意:当suggest表示暗示,insist表示坚持观点,事实时,后接的宾语从句应当用真实语气。
hissilencesuggestedthatheagreedwithmydecision.
heinsiststhatdoingmorningexercisesdoesgoodtopeople’shealth.
3.itissuggested/advised/ordered/requested/required…+that从句(should)do
itisproposedthatmorestudentsshouldgotouniversity.
4.myadvice/suggestion/request/requirement/order/proposal…+is+表语从句(should)do
myadviceisthatyoushouldpractisespeakingenglishasoftenaspossible.
theorderfromthecommanderwasthatthetroopsshouldsetoffforthefrontimmediately.
5.hissuggestion/advice/request/requirement…+同位语从句(should)do+is..
therequestthattheyshouldgetmoreisreasonable.
6.itisnatural/necessary/strange+that从句(should)do表惊奇、怀疑、惋惜、不满、理应如此等。
it’sstrangethatheshouldhavemissedthetrain.(表竟然)
itisimportantthatweshouldlearnfromothers.(表理应如此)
itisapitythatheshouldnotgowithus.(表惊讶、不满)
7.wish+thatclause(did/were与现在相反)共
wish+thatclause(would/could/might+do与将来相反)
wish+thatclause(haddone与过去相反)
iwishicouldgowiththemtomorrow.
iwishihadnevermethim.
8.itis(high/about)time+从句(did或shoulddo)
itis(high/about)timewewenthome.
9.wouldrather+clause(did与现在或将来相反);(haddone与过去相反)
iwouldratheryoucametomorrow.
iwouldratheryouhadn’ttoldherthenews.
10.省去条件从句或主句:表示虚拟语气的主句或从句有时可以省略,但其含义仍可以推知。
①省去条件从句
youcouldhavewashedyourclothesyourself.你本可以自已洗衣服的。
省去了"ifyouhadwantedto")(事实是:你自己没洗衣服,因为你不想洗。)
②省去主句(常用以表示愿望)ifonly+clause(did/were与现在相反)/(would/could/might+do与将来相反)/(haddone与过去相反)“要是…….就好了“
ifmygrandmotherwerewithme!如果我的祖母与我在一起多好啊!(事实是:祖母已不在世。)
ifonlyshehadnotleft!如果她没走就好了!(事实是:她已经走了。)
ifonlyhewouldcometomorrow!
ifonlyihadtakenheradvice!
ifonlyiweretenyearsyounger!
注意:onlyif是“只要”的意思,从句中用陈述语气。
11.asif+clause(did/were与现在相反)/(would/could/might+do与将来相反)/(haddone与过去相反)
shetreatskateasifshewereherowndaughter.
theytalkedasiftheyhadbeenfriendsforyears.
12.wouldlike/was/weretohavedonesomething
iwouldliketohaveattendedtheparty,butoneofmyfriendscametoseeme.
13.butfor+名词
butforyourhelpwecouldn’thavesucceededintheexperiment.
14.注意虚拟条件从句的特殊形式
withoutelectricity,humanlifewouldbequitedifferenttoday.
withouttheairtoholdsomeofthesun'sheat,theearthatnightwouldbefreezingcold.
15.注意转折语气连词引导的虚拟语气
hehesitatedforamomentbeforekickingtheball,otherwisehewouldhavescoredagoal.
itoldsallyhowtogethere,butperhapsishouldhavewrittenitdownforher.
thecaptainkeptcalmintheterriblestorm,otherwisetheaccidentwouldn'thavebeenprevented.
yesterday,janewalkedawayfromthediscussion.otherwise,shemighthavesaidsomethingshewouldregretlater.
16.注意分词和独立结构引导的虚拟语气
givenmorethantwohours,wecouldhavedonetheworkbetter.
nothavingfinishedthework,hecouldn'thaveseenthisfilm.
【高考预测】
1.whydidn'tyoutellmetherewasnomeetingtoday?i_____allthewayhere_____theheavysnow.
a.needn'thavedriven;through b.can'thavedriven;across共
c.mustn'thavedriven;through d.shouldn'thavedriven;cross
2.—mum,it’snoneofmybusiness.why_____icare?
—justbecausesheisyoursister.
a.can b.should c.will d.may
3.—ididn’tknowyouweregoodfriends.
—you_____.ihaveknownhersinceshemovedhere.you werestudyingabroadthen.
a.mayhave b.needn’thave c.couldn’thave d.musthave
4.—theconcertwaswonderful!
—really?howiwishi______tothetheatrewithyouyesterday!
a.hadgone b.mightgo c.wereabletogo d.wouldgo
5.thetwostrangershavebeentalkingintheparkforalongtimeasthoughthey______oldfriends.
a.are b.shouldbe c.were d.wouldbe
6.______theheavyrain,we______thetown.
a.butfor;shouldhavereached b.becauseof;wouldhavereached
c.duringtheperiodof;wewouldreach d.inspiteof;weshouldhavereached
7.—ifwilliam_______,he_______thatgreenpeach.
—luckilyhewassenttothehospitalintime.
a.waswarned;wouldnottake b.hadbeenwarned;wouldnothavetaken
c.wouldbewarned;hadnottaken d.wouldhavebeenwarned;hadnottaken
8.—isitgoodtolookupeverynewwordwhenicomeacrossitinreading?
—no.you______becauseyouarelikelytoguessthemeaningfromthecontext.
a.can’t b.mustn’t c.don’thaveto d.oughtnotto
9.—______iuseyourcomputertosendane-mail?
—yes,you______.butyoumustn’tkeepittoolong.i’llsurftheinternetaftersupper.共
a.could;could b.could;must c.can;can d.could;can
10.whenhelivedthere,he______gotothatbookshopatthecornerwithhisgirlfriendafterworkeveryday.
a.would b.should c.hadbetter d.might
11.—ihearyou’vegotasetofaustraliancoins.______ihavealook?
—yes,certainly.
a.do b.may c.shall d.should
12.—whathappenedtotheyoungtreesweplantedlastweek?
—thetrees______well,butididn’twaterthem.
a.mightgrow b.needn’thavegrown c.wouldgrow d.wouldhavegrown
13.what______hadbobwalkedfarther,asfarastheriverbank?
a.wouldhappen b.couldhappen c.wouldhavehappened d.needn’thavehappened
14.hurryup,tom.it’shightimewe______tothetheater.
a.will b.shall c.aregoingto d.went
15.—doyouthinkhewilldomeafavor?
—asfarasiknow,heisthelastonetohelpothers.he______bepreparedtogiveyouahand,though.
a.might b.must c.can d.should
16.eventhoughi’dhurtmyleg,i______swimbacktotheriverbank.
a.could b.might c.hadto d.wasableto
17.—itisrathercoldhere.shallwelightafire?共
—no,we______becausethingsareeasytocatchfire.
a.won’t b.can’t c.mustn’t d.needn’t
18.—wouldyouhavetoldhimtheanswerhaditbeenpossible?
—iwouldhave,buti______sobusythen.
a.hadbeen b.were c.was d.wouldbe
19.theyoungmaninsistedthathe______thesewatchesand______free.
a.stole,set b.hadstolen,beset c.steal,beset d.hadstolen;mustbeset
20.i______youraddress,otherwisei______youlongbefore.
a.hadforgotten,hadvisited b.forgot,havevisited
c.forgot,wouldhavevisited d.haveforgotten,wouldvisit
21.i______youabeautifulpresentforyourbirthday,butiwasshortofmoneyatthattime.
a.wouldbuy b.hadbought c.wouldliketohavebought d.musthavebought
22.—doyoufeellike________thereorshallwetakeabus?
—i’dliketowalk.butsincethereisn'tmuchtimeleft,i'dratherwe________ataxi.
a.walking,hire b.towalk,hire c.towalk,hired d.walking,hired23.—misswhitehasdecidedtoexploreintheforestbyherself.
—she________askherboyfriendtoifshe________gowalkingintheforest.
a.needn'tto,darestohttp:/ b.doesn'tneed,dares c.neednotto,dareto d.needn't,dare24.hisfailureintheexamsuggestedthathe__________theteacher’sinstructions.
a.can’thavefollowedhttp:/ b.needn’thavefollowed
c.mustn’thavefollowed d.shouldn’thavefollowed
25.i_________you,butididn’tthinkyouwouldlistentome.
a.couldhavetold b.musthavetold c.shouldtell d.mightrell共
26.—mslinlooksratherakindlady.
—butinfactsheiscoldandhardonus.you_______believeit!http:/
a.shouldn’t b.wouldn’t c.mustn’t d.needn’t
27.themanager’shealthwasgettingworseandworsebecauseofheavyburden,sothedoctorstrongly
recommendedthathe aholiday.
a.took b.wouldtake c.musttake d.take
28.—it’ssocold!whynotclosethedoor?
—sorry.it .i’llhaveitrepairedsoon.
a.won’tshut b.won’tbeshut c.hasn’tshut d.isn’tshut
29.iwouldn’tmarrypatevenifshe thelastwomanonearth.
a.is b.was c.hadbeen d.were
30.manystudentswilltakepartintheschoolsportsmeetingthisweek,soshesuggestedthattheclassmeeting_______heldonsaturday.
a.notbe b.nottobe c.benot d.benotto
31.________theproblem,hewouldn'thavecommittedthosemistakes.
a.ifheunderstood b.hadheunderstood c.whenhehadunderstood d.ifhewouldunderstood
32.—butthosearesize44.youmightneedasmallersize.
—yes,i______abitofweight.ihavebeentryingtoloseweight!
a.willhavelost b.shouldhavelost c.mayhavelost d.can’tlose
33.—areyougoingtolloyd’sbirthdaypartyonfriday?
—onlyifit______,hesaidhewashavingapicnicparty.
a.wouldn’train b.doesn’train c.won’train d.hadn’trained
34.ifsanlugroup__________melaminetothemilk,thebabies________toomuchfromkidneystones.
a.didn’tadd;wouldnotsuffered b.hadn’tadded;wouldn’thavesuffered
c.hasn’tadded;wouldn’thavesuffered d.hadn’tadded;wouldhavesuffered
35.—theresearchonthenewbirdfluvirusvaccineischallenginganddemanding.whodoyouthinkcandothe
job?
—____mystudentshaveatry?
a.shall b.will c.could d.should
【参考答案】1-5abcac 6-10abcda 11-15bdcda 16-20dccbc
21-25cddaa 26-30bdada 31-35bcbba
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