1、情態(tài)動詞的基本用法,一、情態(tài)動詞表示推測 表示可能性的層次比較：,(1)must常用于肯定句，一般不用于否定句和疑問句；can常用于否定句、疑問句或感嘆句中，表示疑惑、驚訝或不相信等意思；could既可用于肯定句又可用于否定句和疑問句中。 (2)would, could, should, might不一定與過去時間有關(guān)，也可以表示可能性弱于與他們相應(yīng)的現(xiàn)在時形式。 (3)should/ought to表示推測時，表示確定或可能性大的期望，即合乎理想的情況或結(jié)果。,(1)You be hungry alreadyyou had lunch only two hours ago! 解析句意：兩小時

2、前你剛吃過午飯，你不可能已經(jīng)餓了。根據(jù)后面的語境可推知前面是“不能夠，不可能”，故用cant。,cant,二、情態(tài)動詞表示請求、允許、允諾 英語中表示請求、允許和允諾的情態(tài)動詞通常有： can，may, could, might, shall, will和would等。 1.Can I.? May I.? Could I.？和Might I.？都可以表示征詢聽話人的許可。 Could I use your bike tomorrow? 明天我可以用一下你的自行車嗎？ Yes, you can. (No，Im afraid not.) 可以的。(恐怕不行。),此處could，might不表示過去

3、，而是表示更委婉的語氣?？隙ɑ卮鹨话阌肶es, please/Sure(Certainly/Of course)，you can (may)，不能用could和might。否定回答一般用mustnt或cannot，也可用may not, had better not，或者直接用No，Im afraid not.,2.Will/Would you.？表示請求。would表示更客氣，有時也用Wont you.？意為“好嗎？”“要不要”。 Will you close the window？請你把窗戶關(guān)上好嗎？ Wont you drink some more coffee? 要不要再來一點(diǎn)咖啡？

4、3.shall用于第一、三人稱的疑問句中時表示征求意見。 Shall I get you some tea？我給你倒點(diǎn)茶好嗎？ Shall the boy wait outside? 讓那男孩在外面等好嗎？,4.shall用于第二、三人稱的陳述句時，往往表示給對方(you)或第三者(he, she, they)以允諾、命令、決心、警告或威脅等，在法律、條約、協(xié)定等文件中可以表示義務(wù)、規(guī)定等。 You shall get a birthday present. 你會得到生日禮物的。(允諾) You shall be sorry for it one day, I tell you, 有一天你會后

5、悔的，我告訴你。(警告) Each citizen shall carry his identification card when travelling. 旅游時每個市民務(wù)必帶上身份證。(規(guī)定),(2)(2011陜西，24)Will you read me a story, Mummy? OK. You have one if you go to bed as soon as possible. 解析句意：媽媽，給我講個故事好嗎？好，如果你盡快上床睡覺，我就給你講一個?？疾榍閼B(tài)動詞。shall在此處表示“允諾”。,shall,三、情態(tài)動詞表示必要性 表示“必要性”的情態(tài)動詞通常有： must

6、, should，ought to，have to。 1.ought to與should意思大體相同，但ought to語氣比should重，往往表示從法律或道義上“應(yīng)該”。 You are his father and ought to take care of him. 你是他父親，應(yīng)當(dāng)照顧他。(有責(zé)任，從道義上應(yīng)該) Young people should show respect for the old. 年輕人應(yīng)該尊重老年人。,2.have to表示“必須，不得不”，這個意義與must很接近，但must表示主觀意志，而have to表示由于客觀因素不得不做某事。 I told her

7、 that she must give up smoking. 我叫她必須戒煙。 I have to hand in my term paper before 5：00 p.m. today. 我必須今天下午5點(diǎn)前交學(xué)期論文。,(3)I dont care what people think. Well, you . 解析句意：我不介意別人怎么想。噢，你應(yīng)該那么做。根據(jù)語境可知，應(yīng)用should，意為“應(yīng)該”，表示一種建議，勸說。,should,四、情態(tài)動詞表示能力 表示“能力”的情態(tài)動詞有：can, could, be able to。 1.情態(tài)動詞can只有兩種時態(tài)形式，現(xiàn)在時can和過去

8、式could，而be able to有多種時態(tài)形式。 Mary can play the piano. She has been able to play it since she was five.瑪麗會彈鋼琴，她5歲起就會彈了。 2.表示過去能力時，was/were able to表示經(jīng)過一番努力后取得了成功。相當(dāng)于manage to do或succeed in doing，而could沒有這個含義。 Yesterday I was able to get home before the heavy rain. 昨天我在下大雨前趕到了家里。,(4)The fire spread throu

9、gh the hotel very quickly but everyone (able) get out. 解析was able to表示經(jīng)過努力能夠做到，強(qiáng)調(diào)成功。句意：大火很快蔓延了整個賓館，但是大家都成功地離開了。,was able to,can與be able to的區(qū)別 (1)can只能用在一般現(xiàn)在時和一般過去時中，而be able to有更多的時態(tài)。 (2)表示過去特定的能力或經(jīng)過努力才具備的能力，只能用be able to。 I talked with her for a long time, and finally I was able to make her believe

10、 me. 我和她談了很長時間，最終才贏得她的信任。 (3)用在其他動詞，如might, may, would后只能用be able to。,用can, could, be able to的適當(dāng)形式填空 (5)Though the building was on fire, they go out safely. (6)Im going to Europe on vacation with John if I find the money. (7)Hows your new babysitter? We not ask for a better one. All our kids love he

11、r so much. (8)The police still havent found the lost child，but theyre doing all they . (9)You be too careful when driving.,were able to,cant,could,can,cant,五、“情態(tài)動詞have done”的用法 “情態(tài)動詞have done”的常見用法包括： 1.must have done表示對過去已發(fā)生的事情進(jìn)行肯定的推斷，只用于肯定句中，意為“一定，必定”，其否定形式為：cant/cannot have done。 It must have rai

12、ned last night, for the road was quite wet. 昨晚肯定下雨了，因?yàn)槁访媸殖睗瘛?I saw Mr Wang just now. He couldnt have gone abroad. 剛剛我還看見王先生了，他不可能已經(jīng)出國了。,2.could have done意為“本來可以，本來能夠”，表示虛擬語氣。 You could have made greater progress, but you didnt try your best.你本來可以取得更大的進(jìn)步，但是你沒有努力。 3.may/might have done表示對過去已發(fā)生的事情進(jìn)行推斷

13、，意為“可能/或許已經(jīng)”。其否定形式為： may/might not have done意為“可能沒有做”。 Its no use going to his house. He may not have gone home. He may have gone somewhere else.去他家沒用。 他可能沒有回家，可能已經(jīng)去了別的地方。,4.should/ought to have done表示本應(yīng)該做某事，卻沒有做，含有責(zé)備或后悔之意。其否定形式為should not/ought not to have done表示本不該做某事卻做了。 With all the work finishe

14、d, I should have gone to the party last night.所有的工作都做完了，我昨晚本該去參加宴會的。 You ought not to have made fun of him. He is not the one you laugh at but learn from.你本不應(yīng)該取笑他的。他不是你要嘲笑的人而是你應(yīng)該學(xué)習(xí)的榜樣。,5.neednt have done表示本沒有必要做某事卻做了，多用于否定句中。 You neednt have waken me up；I dont have to go to work today.你本不必叫醒我的；我今天不上

15、班。 注意： neednt do表示“沒有必要去做某事”，時間上應(yīng)該是現(xiàn)在或?qū)怼?You neednt telephone him now, for he isnt at home. 你現(xiàn)在不必打電話給他，因?yàn)樗辉诩摇?(10)Mark have hurried. After driving at top speed, he arrived half an hour early. 解析考查“情態(tài)動詞have done”的用法。neednt have done表示“本來不必要做但已經(jīng)做了”，符合語境。,neednt,完成句子 (11)I (我本來可以幫助你的), but I was too

16、busy then. (12)You (一定是睡得很晚) last night. Your eyes are red. (13)I (本應(yīng)該做作業(yè)) last night, but I went to the cinema.,could have helped you,must have slept late,should have done my homework,六、情態(tài)動詞的其他用法 情態(tài)動詞的其他用法主要有： 1.情態(tài)動詞need和dare的用法。 (1)need和dare作情態(tài)動詞時常用于否定句、疑問句或條件句中，無人稱和數(shù)的變化，疑問句和否定句中不加助動詞。 Need I tele

17、phone him now? 需要我現(xiàn)在打電話給他嗎？ She dare not go out alone at night. 她晚上不敢一個人出去。,(2)need和dare用于實(shí)義動詞時，有詞形變化。變成否定句、疑問句時，要加助動詞。 You dont need to do it yourself. 你不必親自做這件事。 We should dare to give our own opinion. 我們要敢于提出自己的觀點(diǎn)。,2.幾個可以表示某一特定的語氣或態(tài)度的情態(tài)動詞 (1)can可以用來表示驚異、懷疑、不相信的態(tài)度，主要用于否定句、疑問句或感嘆句中。 How can you be

18、so careless？你怎么這么粗心？ (2)must用于條件句或疑問句中，可以用來表示責(zé)備、抱怨的感情色彩，意為“偏要，硬要”。 Why must you be so late? 你為何非要這么晚來呢？ (3)may表示愿望、祝福時，有“但愿，?！敝?。 May you succeed！祝你成功！,(4)should表示驚訝，不以為然等情緒，用于某些句型中，多譯為“竟然”。 It seems unfair that this should happen to me. 這種事情竟然發(fā)生在我的身上，好像不公平。 (5)will的用法 will表示“意愿，意志”，would表示過去時間的“意愿、

19、意志”。will還可以表示某種傾向或習(xí)慣性動作，意為“總會，老是”，其否定結(jié)構(gòu)意為“不肯，不能”。 I will do anything for you.我愿意為你做任何事。 The door wont open.這門打不開。 Every time she was in trouble, she would go to him for help.每次遇到麻煩她都會向他求助。,3.情態(tài)動詞的一些習(xí)慣用法 (1)cannot/can never.too或cannot.enough表示“無論怎么也不過分；越越好”。 You cannot be too careful.你越細(xì)心越好。 (2)canno

20、t help doing./cannot help but do./cannot but do.表示“禁不??；不得不”。,I couldnt help jumping up when I saw him. 一看到他我情不自禁地跳了起來。 I cannot but admire his bravery. 我不得不佩服他的勇敢。 (3)“may/might as well動詞原形”表示“還不如，不妨”，相當(dāng)于had better。 It is very late, so you may/might as well go to bed. 夜深了，你不妨去睡吧。,(14)(2011遼寧，21)If y

21、ou go, at least wait until the storm is over. 解析句意：如果你偏要走，至少要等到暴風(fēng)雨停了?？疾榍閼B(tài)動詞的用法。If you must do sth為固定用法，意為：如果你偏要做某事。,must,(15)The door open, no matter how hard Grandma pushed. 解析句意：無論Grandma如何推，門總是打不開。will表示某種傾向或習(xí)慣性動作，意為“總會，老是”，其否定為“不能，不肯”，在此是過去時態(tài)，故用“wouldnt”。,wouldnt,虛擬語氣的考查要點(diǎn),一、虛擬語氣用于條件狀語從句 1.表示與現(xiàn)在

22、事實(shí)相反的假設(shè)，條件狀語從句中的謂語動詞用一般過去時(be動詞用were)，而主句中的謂語動詞用“would/should/could/might動詞原形”。 If I were you, I would buy that house. If he had time, he should go with you. 2.表示與過去的事實(shí)相反，條件狀語從句中的謂語動詞用過去完成時，主句中的謂語動詞則用“would/should/might/couldhave過去分詞”。 If he had taken my advice, he would have succeeded in passing th

23、e examination.,3.表示與將來事實(shí)相反，條件狀語從句中的謂語動詞用一般過去時或“should/were to動詞原形”，而主句中的謂語動詞則用“would/should/could/might動詞原形”。 If it were to rain tomorrow, the football match would be put off. 4.當(dāng)條件狀語從句表示的行為和主句表示的行為所發(fā)生的時間不一致時，動詞的形式要根據(jù)它所表示的時間作相應(yīng)調(diào)整。 If they had worked hard, they would be very tired now.(從句說的是過去，主句指的是現(xiàn)

24、在),用所給動詞的適當(dāng)形式填空 (1)If I (have) time next week, I would go to the party. (2)If I (be) you, I should go and see the dentist at once. (3)If you had arrived at the station ten minutes earlier, you (catch) the train.,had,were,would have caught,二、虛擬語氣用于名詞性從句 1.虛擬語氣在賓語從句中的運(yùn)用。 (1)“wish賓語從句”表示不能實(shí)現(xiàn)的愿望，譯為“要是就好

25、了”等。表示現(xiàn)在不能實(shí)現(xiàn)的愿望，從句中的謂語動詞用一般過去時；表示將來不能實(shí)現(xiàn)的愿望，從句中的謂語動詞用“would/could動詞原形”；表示過去不能實(shí)現(xiàn)的愿望，從句中的謂語動詞用“had過去分詞”或“could/shouldhave過去分詞”。,I wish it were spring all the year round. I wish I had known the answer. I wish I could fly like a bird. (2)在表示建議、要求、命令等動詞后的賓語從句中，謂語動詞用“should動詞原形”，should可以省略。 常見的動詞有： suggest

26、, advise, propose, demand, require, insist, request, command, order等。 She suggested we (should) leave here at once. The doctor ordered she should be operated on.,suggest除了“建議”外，還有“暗示，表明”的意思，若當(dāng)“暗示”時，suggest后跟陳述語氣。 insist當(dāng)“堅(jiān)持主張、要求”時后跟虛擬語氣；若當(dāng)“堅(jiān)持一說法、事實(shí)”時，后用陳述語氣。,2.虛擬語氣在同位語從句和表語從句中的運(yùn)用。 表示建議、要求、命令等的名詞，如ad

27、vice, idea, order, demand, plan, proposal, suggestion, request等，其后的表語從句和同位語從句中謂語動詞用“(should)動詞原形”， should可以省略。 His suggestion that we (should) go to Shanghai is wonderful. My idea is that they (should) pay 100 dollars.,3.虛擬語氣在主語從句中的運(yùn)用。 在主語從句中，謂語動詞的虛擬語氣用“(should)動詞原形”的結(jié)構(gòu)，表示驚奇、不相信、理應(yīng)如此等。 It is necessa

28、ry (important, natural, strange, etc.) that we (should) clean the room every day. It was a pity (a shame, no wonder, etc.) that you (should) be so careless. It will be desired (suggested, decided, ordered, requested, proposed, etc.) that she (should) finish her homework this afternoon.,用所給詞的適當(dāng)形式填空 (

29、4)Where are the children? The dinners going to be completely ruined. I wish they (not be) always late. (5)It is requested that Class Two (give) a performance at the English evening. (6)He insisted that a deadline (set) for completing the task.,were not,(should) give,(should) be set,三、虛擬語氣在其他場合的運(yùn)用 1.

30、虛擬語氣在as if/as though, even if/even though等引導(dǎo)的表語從句或狀語從句中，如果從句表示的動作發(fā)生在過去，用過去完成時；指現(xiàn)在狀況，則用一般過去時；指將來狀況則用過去將來時。 He did it as if he were an expert. Even if she were here, she could not solve the problem.,2.虛擬語氣用于定語從句中。 這種從句常用于句型“It is (high)time (that).”中，定語從句的謂語動詞用一般過去時(be用were)或“should動詞原形”，意思是“(現(xiàn)在)該”。 I

31、ts time that I picked up my daughter. Its high time we were going.,在It is time that.should動詞原形.結(jié)構(gòu)中，should不能省略。,3.虛擬語氣用在if only引導(dǎo)的感嘆句中。 If only I were a pilot. If only I had taken his advice. 4.虛擬語氣在一些簡單句中的運(yùn)用。 (1)情態(tài)動詞的過去式用于現(xiàn)在時態(tài)時，表示說話人謙虛、客氣、有禮貌或語氣委婉，常出現(xiàn)在日常會話中。 It would be better for you not to stay up

32、 too late. Would you be kind enough to close the door? (2)用于一些習(xí)慣表達(dá)法中。 Would you like a cup of tea? I would rather not tell you.,(7)(2012北京，35)Dont handle the vase as if it made of steel. 解析句意：拿花瓶時不要認(rèn)為它好像是由鋼鐵做的。as if“仿佛，好像”?；ㄆ坎⒎怯射撹F制作，與事實(shí)相反，故用虛擬語氣。又因前面動詞“Dont”可知是與現(xiàn)在事實(shí)相反，故用were。,were,易錯點(diǎn)1情態(tài)動詞have done結(jié)構(gòu)的誤用,用括號內(nèi)動詞的適當(dāng)形式填空 What a pity! Considering his ability and experience, he _ (do) better. 解析句意：真是遺憾！考慮到他的能力和經(jīng)驗(yàn)，他當(dāng)時有可能做的更好些。,might have done,【即時小練】 The weather turned out to