情態(tài)動詞和虛擬語氣講義

1、情態(tài)動詞和虛擬語氣講義考點一：情態(tài)動詞的基本用法1. can, could, may, might 的用法1）can表示能力，意為"能夠；懂得；會” 。could表示過去的能力；其將來時用be able to代替。This mach ine can perform two millio n calculati ons per sec ond.I can speak five Ian guages.注意：be able to表示"能夠做某事而且做成功了”。He was able to do that without any help.他不需要任何幫助就完成了這項工作。2）ca

2、n, could, may, might表示請求 （permission）、允許或許可。常用在口語中，其中的 could語氣較委婉，不用于肯定句，答語要用can; could都還表示委婉客氣的提出問題或陳述看法；might表示委婉的請求。The goalkeeper can 'ha ndle the ball outside the pen alty area （禁區(qū)）.Could I use your bike?我可以用你的自行車嗎？Yes, you can ./I'm afraid not. 可以，用吧。No, you can ' t/must不行。t.May/Ca

3、n take the book out? 我可以把這本書帶走嗎？Yes, you may/ca n. 可以。No, you may not.不可以。（委婉）No, you can ' t/mustn 不行。（強烈）3）can與表示感官和思維的動詞連用。You can really taste the garlic in that soup.You can imagi ne how anno yed she was!2. must的用法。must既表示義務(wù)或強制，意為“必須；一定要”；還可表示肯定性，意為“必然會；肯定會”；作“偏要；硬要”解時，用于第二人稱時，表示不耐煩或令人不愉快的事

4、情；用于其他人稱， 表示主語“固執(zhí)”的意味。If you can ' t finish the book by then, you must come and renew it.I ' m afraid I must go now; I promised to be home at ten.Don 'bet on the horse race; you must lose in the long run.If you must know, I' m going to help him look for an apartment.Jane was n ever a

5、 pleasa nt young girl. After you gave her your advice, she must go and do the opposite.must的否定形式有兩種：當(dāng)must表示“強制或義務(wù)”時，其否定意義為“一定不要”，表示不許或禁止，將 must do改為must not do；當(dāng)must表示“必須”時，其否定含義為“不必”，將must do改為 need not do 或 don' t have toWe mustn ' t waste our time我們不應(yīng)該浪費時間。You need not/don ' t have to

6、 get up at six tomorrow morni明天早上你不必六點起床。注意：1） must可以用作名詞，意為“必須有的東西（做的事）。Don 'miss latest play; it's a must. /Warm clothes are a must in the mountains.2）詞組 be sure to, be certain to, be bound to, be due to 者E有“一定； 肯定； 務(wù)必”等意義。He in formed us that the boat was due to leave at 4. /The pla n is

7、bound to succeed.3. shall的用法。在疑問句中，用于第一、三人稱，表示征求對方的意見；用于第二、三人稱時表允諾，警告，命令，威脅等；在法律、條約、規(guī)章等文件中，表示義務(wù)、規(guī)定。What shall I wear on the jour ney? /Shall he start at once or wait for a while?She shall get her share. /You shall fail if you don ' t work harder.House owners shall keep their garde ns in a n eat

8、and ordinary state.Each citizen shall carry his identification card when traveling.4. should 和 ought to 的用法。should表示"勸告、建議、命令”，其同義詞是 ought to （否定式ought not to do） ； should還可表示義 務(wù)，意為“應(yīng)該”；也可表示驚訝，憂慮，惋惜等情緒，意為“竟會；竟然”，常用在I m surprised;It worries me; It 's a pity; You can't imagine 等結(jié)構(gòu)中。You sh

9、ould/ought to go to class right away.He should do some work, but he doesn 'twant to.I find it quite astonishing that he should be so rude to you./You can't imagine that a well-behaved gen tlema n should be rude to a lady.5. will和 would的用法。will可以表示意志，決心或愿望；也可表示經(jīng)常性、習(xí)慣性、傾向性，表示某事總是發(fā)生或一般如此；也可表請求；

10、還可表示“老是”，用于描述某人奇異或令人煩的習(xí)性，用在第三人稱。would也可表示愿望，還表示過去的習(xí)慣行為，用于第二人稱作主語的疑問句中，表示對對方的請求。Surely we will support all the people in the world in their struggle for peace.I will come up and help you clea n the room in a mome nt.Oil will float on water./ Accide nts will happe n.He will sit there hour after hour l

11、ooking at the traffic go by./Trish will keep asking silly questions.During the vacation he would visit me every week.注意：won't或wouldn't表示“堅決地拒絕”I won 'tlisten to your nonsense./We urged him to take a rest, but he wouldn 'hear of it.考點二、情態(tài)動詞表“可能性”的用法：1. can表可能性，含有驚訝、懷疑、不相信的語氣，常用在否定句、疑問

12、句、感嘆句中，意為“可能” ；can be用于推測某人或某物一時的情況，意為“有時候會”；could表輕微的懷疑或委婉的看法。Can what he said be true? /What can he possibly mean?It can be very cold here at ni ght. /The boy can be very annoying.His story could be true, but I hardly think it is.注意：can表示“可能性”，有時也可用在肯定句中，但表示的是理論上的可能性，不涉及是否真的會發(fā)生。The invention can b

13、e improved./The word bank" can have several meanings.2. may表可能性，用于推測，暗指不確定，不用于疑問句，在疑問句中表示“可能”時，通常用be likely to或do you think結(jié)構(gòu)；當(dāng)句中出現(xiàn)I am afraid, I am not sure等表示不確定含義時，常選用may或 might ； may表示的可能性比 might大一些。It is feared that many workers may lose their jobs this win ter. /I am afraid he may be wait

14、 ing for you.Is she likely to come this after noon?3. must可以表示推測，只能用在肯定句中，表示"一定”或"必定”之意，其否定形式是can'couldn ', 意為"不可能”。Must be doing表示"現(xiàn)在肯定正在做”。Whose new bike can it be?It must be Liu Don g's. I know his father has just bought him a new one.You look happy. You must be ha

15、vi ng a good time.He can 'be in Beiji ng now because I have see n him just now.4. should表示期待，用于表達(dá)合理的推斷（“應(yīng)該）或明顯的結(jié)果（可能），所期待的事是事實。It is three o 'clock, the football game should begi n now.Mary took dancing less ons for years; she should be an excelle nt dan cer.注意：詞組 be supposed to, be meant to

16、均有“應(yīng)該；必須”等情態(tài)含義。Everybody is supposed to wear a seat belt in the car.考點三、情態(tài)動詞+不定式的完成式“情態(tài)動詞+不定式的完成式”在高考中出現(xiàn)的頻率也相當(dāng)高，其中尤以must have done出現(xiàn)次數(shù)最多。下表是“情態(tài)動詞 +不定式的完成式”的結(jié)構(gòu)和含義。結(jié)構(gòu)含義could have done過去可以做而實際上沒做。 表推測，過去可能做了某事“本來可以做”。can '/could n 'have done過去不可能發(fā)生的事情，是must have done 的否定式。may/might have done對過去

17、發(fā)生的行為的推測。“可能會做”。must have done對過去已發(fā)生的行為的推斷?！耙欢ㄒ炎觥薄 eed have done本來需要做而實際上已做了。“本有必要做”。n eed n'thave done本來不需要做而實際上沒做。“本不必做”。should have done本來應(yīng)該做而實際上沒做。“本應(yīng)該做”。should n'thave done本來不應(yīng)該組哦而實際上做了?！氨静粦?yīng)該做”。ought to have done過去應(yīng)該做而實際上沒做?！氨緫?yīng)該做”。will have done推測將來某個時間前已經(jīng)完成?！翱赡芤呀?jīng)做”。You could have done

18、 better, but you didn 'try your best.你本可做的更好，但你不盡力。They can 'have gone out because the light is on.他們不可能用光了，因為燈還亮。He may have finished the exercises, but he didn 'thand in. 他可能完成了作業(yè)，但沒交。He is notin. He must have gone to Shanghai. 他不在家，肯定去上海了。You n eed n'thave watered the flowers, for

19、 it going to rain. 你本沒有必要澆花，因為天要下雨了。You should have started earlier, but you didn ' 你本應(yīng)該早一點出發(fā)的，但你沒有?？键c四、情態(tài)動詞的某些慣用語和句型1. can的慣用語1) cann ot (help/choose) but+ 原形不得不；只能I cannot help but tell the truth.2) can but+ 原形 只好；不得不 We can but agree with you3) cannot help doing不得不；忍不住4) can 'help sb. doi

20、 ng sth.不能使某人不作某事lean 'help sayi ng that.5) can 'help it 控制不住，沒有辦法Why are you cryin g? lean 'help it.6) cann ot tooto 無論怎樣也不為過2. may/might的慣用語1) may/might well do很可能；極有可能These are excelle nt photographs and we may well be able to use them in our magaz ine.You might well find that you n e

21、ed more by the weeke nd.2) may/might as well 最好(had better)It 'no good wait ing for the bus. We might as well walk.If you are not going to eat that pizza I may as well throw it out.3) may/might as well doas do與其做某事，不如做某事You might as well throw the money away as lend it to him.One may as well not

22、 know a thing at all as know it but imperfectly.4) maybut盡管但是He may be lazy, but he can work very hard when he feel like it.5) may you/he/they etc do sth. 祝愿 May both the bride and groom have long and happy life.3. 用作情態(tài)動詞的其他短語1) would rather, would sooner, would (just) as soon, had rather, had bette

23、r, had sooner 可用作情態(tài)動詞。 The soldier would sooner die than surrender. 這個戰(zhàn)士寧可死也不投降。If you don ' t like to swim, you may justwaell stay at home.如果你不喜歡游泳，最好呆在家里。這些短語后一般直接跟動詞原形.would (had) rather, would (had) sooner, would (just) as soon 后可跟that引導(dǎo)的從句，that常省去，從句要用虛擬語氣。對現(xiàn)在和將來的假設(shè)用過去時，對過去的假設(shè) 用過去完成時。I woul

24、d rather you came on Sun day. 我想讓你周日來。I would sooner you hadn ' t askedpmiakt(yesterday.我寧愿你昨天沒讓我發(fā)言。2) so that/in order that 接may, might, can, should ; for fear that 后接 might, should ; in case that后接 should。 He rested in order that he might work harder.We all seemed afraid to say what was in our

25、 min ds, for fear that it might start trouble.Better cha in up the dog in case he bite/bites.咼考鏈接：1. (2009 四川卷)I don ' t care what people think.Well, you.A. couldB. wouldC. shouldD. might2. (2009 全國卷 I) What do you mean, there are only ten tickets? Therebe twelve.A. shouldB. wouldC. willD. shall

26、3. (2009 湖南卷)一It ' s the office! So youknow eating is not allowed here.Oh, sorry.A. mustB. willC. mayD.n eed4(2009 遼寧卷)The traffic is heavy these days. Iarrive a bit late, so could you save me a place?A. canB. mustC. n eedD.might5. (2009 全國卷 II ) I can ' t leave. She told me that Istayhere u

27、ntil she comes back.A. canB. mustC. willD.may6. (2009 重慶卷)一Hi, Tom . Any idea where Jane is?B. should have bee nShein the classroom . I saw her there just now.A. shall beC. must beD. might have bee n7. （2009 北京卷） One of the few things yousay about English people with certainty is that theytalk a lot

28、 about the weather.A. needB. mustC. shouldD. can虛擬語氣講義一、虛擬條件句，即不大可能發(fā)生的或與事實相反的情況。1）很可能與現(xiàn)在或?qū)淼氖聦嵪喾吹臈l件句。其基本結(jié)構(gòu)是：If + S. +V.（過去式/were）, S. +would/should/could/might +動詞原形。如表示和將來事實相反，if條件句還可用"were to+動詞原形”和"should+動詞原形”來表示。If從句里的be動詞一律用were，沒有人稱與數(shù)的變化。指現(xiàn)在或?qū)淼娜魏螘r候，這一結(jié)構(gòu)中所設(shè)的條件可能與事實相反，結(jié)果從句也不是事實。If I

29、had en ough mon ey, I would buy that coat. 如果我有足夠的錢，我就買那件外套。Sunny would be in time if she got the four-thirty bus.如果桑妮搭上 4點30分的公共汽車，她就會及時趕到。If I were you, I would accept their in vitatio n.如果我是你，我就接受他們的邀請。If you were to die tonight, what would you do right now?如果你今天晚上就要死了，那你現(xiàn)在做什么？2）和過去事實相反的條件句。其基本結(jié)構(gòu)

30、是：If + S. +V.（過去完成式had done）,S. +would/should/could/might have + 過去分詞。此種結(jié)構(gòu)里的條件句所設(shè)的條件并未發(fā)生，因而結(jié)果從句所述的結(jié)果也未實現(xiàn)。If the weather had been nice yesterday, we would have gone to the zoo.女口果昨天天氣好的話，我們就會去動物園了。3 ）錯綜時間條件句通常情況下，在非真實條件句中主句和從句的謂語動詞所指時間是一致的，但有時也可能指不同的時間，這時要根據(jù)上下文的意思采用不同的謂語動詞形式。即：有時if從句和主句所表示的假想情況時間不一致，

31、如從句與現(xiàn)在事實相反， 而主句表示與過去事實相反 ，那么句子兩部分的動詞形式應(yīng) 作相應(yīng)的調(diào)整。You would be much be tter now if you had taken the doctor' s advice.If the weather had been more favorable, the crop would be growing still better.4）含蓄條件句英語中某些假設(shè)的條件句不是通過 if從句表達(dá)出來，而是包含在某些短語、上下文或其他方式中， 其謂語也常用虛擬語氣，我們稱此種結(jié)構(gòu)為含蓄條件句。主要有介詞but for, without等。如

32、：要不是有你幫忙，我們是不會成功的。If it h adn ' t been for your assistanee we wouldn' t have succeeded.=But for your assistanee we wouldn' t have succeeded.=Without your assistanee we wouldn' t have succeeded.Having known in time ,we might have prevented the accident.要是及時得知的話，我們也許能阻止這場 事故。（-ing分詞做條件

33、狀語，暗示條件：If we had kown in time ）Give n more atte ntio n, the tree could have grow n better.如果多留心的話，這樹本來可以長的更好。（-ed分詞做條件狀語，暗示：If the tree had bee n give n more atte nti on）I was too busy at that time, otherwise, I would have called you.我當(dāng)時太忙，否則我就給你打電話了。(副詞otherwise暗示條件)二、可以用在“ (should)+動詞原形”中的虛擬語氣主要有

34、以下幾類：1) 用在 suggest, propose, arran ge, pla n, decide, advise, order, dema nd, request, desire, in sist 等表示 “建議”、“要求”、“命令”、“決定”、“安排”、“計劃”、“主張”的動詞后面接的賓語從句中。這里的 should也可以省略。He suggested/ proposed/ demanded/ advised that they ( should) read the rules carefully. 他建議 /提議 / 要求/勸告他們要仔細(xì)閱讀這些規(guī)則。2) 用在 “It is de

35、sired/ suggested/ requested/ ordered/ proposed/ decided ” 之后由 that 引導(dǎo)的主語從句 中，should也可以省略。It is requested that Miss Yang ( should)give a performanee at the part. 人們要求楊小姐在聚會上表演 一個節(jié)目。3) 用在 suggestion, motion, proposal, order, plan, idea, advice, request, decision, requiry 等名詞后面接的表語從句或同位語從句中，should也可以省略

36、。My idea/ moti on/ advice/ is that we (should) do more eye exercises every day.我的意見是我們每天應(yīng)該多做眼保健操。4) 用在“ It is / was necessary/ important/ strange/incredible ”或“ It is a pity/ a shame/ no wonder ”之 后由that引導(dǎo)的主語從句中，should有“應(yīng)該”、“必須”、“竟然”、“居然”之意。It is necessary that he (should) be sent there at on ce.有必要

37、馬上派他到那里去。It is stra nge that the wheel should turn so slowly. 真奇怪，這個輪子竟然轉(zhuǎn)動得如此之慢。It is a great pity/ shame/ that he should be so conceited.真遺憾，他竟會這樣自高自大。三、其它形式的虛擬語氣1) if only是 但愿”之意，弓I導(dǎo)的從句中的謂語動詞要用虛擬語氣，表示和事實相反的情況。If only I knew her name.要是我知道她的名字就好了。(這是if only引導(dǎo)的從句，表達(dá)的是與事實相反的情況，所以謂語動詞用虛擬語氣，與事實相符的情況用kn

38、ow,與事實相反的情況用其過去式knew)If only he had remembered to send that letter.要是他沒有忘記寄那圭寸信就好了。2) wish的用法用于wish后面的從句，表示與事實相反的情況，或表示將來不太可能實現(xiàn)的愿望。其賓語從句的動 詞形式為：真實狀況 wish后從句動作先于主句動詞動作用過去時或過去完成時，(be的過去式為 were)從句動作與主句動作同時發(fā)生用現(xiàn)在時或過去時，將來不大可能實現(xiàn)的愿望用would/could +動詞原形。I wish I were as tall as you. /He wished he had n't s

39、aid that. /I wish it would rain tomorrow.4) 用于 “it is time從句”中虛擬語氣用于“It is(high,about)time+從句"這一結(jié)構(gòu)中，從句謂語動詞用過去式，表示早該做而仍未做的事。It is high time that we went back to college.5) 用于would rather等引起的從句中虛擬語氣用于wouldhad rather(would prefer)引起的從句中，其謂語動詞用過去式，表示當(dāng)時或?qū)?的情況；其謂語動詞用“ had過去分詞”，表示過去的情況。I would rather

40、 you did n't tell him anything about it.She would prefer that she had not stayed at home last ni ght.咼考鏈接1. （2008 全國卷 I） If the weather had been better, we could have had a picnic. But it ll day.A. rainedB. rainsC. has rainedD. is raining2. （2005 江蘇卷）一Don't you think it necessary that heto M

41、iami but to New York?I agree, but the problem ishe has refused to.A. will not be sent; thatB.not be sent; thatC. should not be sent; whatD.should not send; what3. （2006 湖北卷）fired, your health care and other ben efits will not be immediately cut off.A. Would you beB.Should you beC. Could you beD.Migh

42、t you be4. （ 2009 福建卷）But for the help of my English teacher, Ithe first prize in the English WritingCompetiti on.A. would not winB. would not have won C. would winD. would have won5. （ 2009 天津卷） This prin ter is of good quality. If it eak dow n with in the first year, we wouldrepair it at our expe

43、nse.A. wouldB. shouldC. couldD. might6. （ 2009 浙江卷）The doctor recommended that youswim after eating a large meal.A. wouldn ' tB. couldn ' tC. needn ' t D. shouldn ' t情態(tài)動詞小練1. Why did n't Alex attend the party yesterday evening?He not have wan ted to see me.D. wouldD. mightA. shou

44、ldB mightC. could2. It ' s very cloudy and freezing now.Yes, I ' m afraid itsnowing tonight.A. mustB. n eedC. should go and do the opposite.3. Naturally, after I tell my brother what to do, heA. willB. mayC. canD. must4. No driving after drinking is a rule that every driverobey in our countr

45、y.A. willB shall5. Can I pay the bill by check?Sorry, sir. But in our hotel payme nt A. needB shallC. maybe made in cash.C. willD. canD. can6. Why isn't Cathy here yet?She to be picked up at the station.A. could waitB. must waitC. might be wait ingD. can be wait ing7. She just couldn ' t bel

46、ieve that her husband desert her after he became rich.A. mightB. mustC. shouldD. shall8. Remi nd him that you ' re always there for him, this on purpose?A. shouldB. willC. doesD. could9. We thought he would have won the game.What a pity! He too nervous when playing.A. had bee nB. has bee nC. wasD. would have bee n10. I saw Mr. Li at the meet ing yesterday.Did you? Hehave at