一、語(yǔ)氣的定義和種類(lèi)
l、語(yǔ)氣：語(yǔ)氣是動(dòng)詞的一種形式，它表示說(shuō)話(huà)人對(duì)某一行為或事情的看法和態(tài)度。
2、語(yǔ)氣的種類(lèi)：
(1)陳述語(yǔ)氣: 表示動(dòng)作或狀態(tài)是現(xiàn)實(shí)的、確定的或符合事實(shí)的，用于陳述句、疑問(wèn)句和某些感嘆句。如：We are not ready. 我們沒(méi)準(zhǔn)備好。What a fine day it is!多好的天氣啊!
(2)祈使語(yǔ)氣: 表示說(shuō)話(huà)人的建議、請(qǐng)求、邀請(qǐng)、命令等。如: Open the door, please。請(qǐng)打開(kāi)門(mén)。
(3)虛擬語(yǔ)氣: 表示動(dòng)作或狀態(tài)不是客觀存在的事實(shí)，而是說(shuō)話(huà)人的主觀愿望、假設(shè)或推測(cè)等。如: If I were you, I should study English. 如果我是你，我就學(xué)英語(yǔ)了。May you succeed! 祝您成功！
二、虛擬語(yǔ)氣在條件從句中的用法
條件句有兩類(lèi)，一類(lèi)是真實(shí)條件句，一類(lèi)是虛擬條件句。如果假設(shè)的情況是有可能發(fā)生的，就是真實(shí)條件何。在這種真實(shí)條件句中的謂語(yǔ)用陳述語(yǔ)氣。如: If it doesn’t rain tomorrow, we will go to the park. 如果明天不下雨，我們就去公園。
如果假設(shè)的情況是過(guò)去或現(xiàn)在都不存在的，或?qū)?lái)不大可能發(fā)生的，則是虛擬條件句。如: If he had seen you yesterday, he would have asked you about it. 如果他昨天見(jiàn)到你，他會(huì)問(wèn)你這件事的。(事實(shí)上他昨天沒(méi)見(jiàn)到你，因此也未能問(wèn)你這件事。)
在含有虛擬條件句的復(fù)合句中，主句和從句的謂語(yǔ)都要用虛擬語(yǔ)氣�，F(xiàn)將虛擬條件從句和主句的動(dòng)詞形式列表如下:
從 句 主 句
與現(xiàn)在事實(shí)相反 動(dòng)詞的過(guò)去式（be的過(guò)去式一般用were） would/ should/ could/ might + 動(dòng)詞原形
與過(guò)去事實(shí)相反 had + 過(guò)去分詞 would/ should/ could/ might + have + 過(guò)去分詞
與將來(lái)事實(shí)相反 動(dòng)詞過(guò)去式，should + 動(dòng)詞原形，were to + 動(dòng)詞原形 would/ should/ could/ might + 動(dòng)詞原形
注: 主句中的should只用于I、we，但在美國(guó)英語(yǔ)中，should常被would代替；從句中的should 可用于各種人稱(chēng)。
l、表示與現(xiàn)在事實(shí)相反的假設(shè)和結(jié)果。如: If my brother were here, everything would be all right. 要是我哥哥在這兒 ，一切都沒(méi)問(wèn)題了。
2、表示與過(guò)去事實(shí)相反的假設(shè)和結(jié)果。如: If you had taken my advice，you wouldn't (couldn’t) have failed in the exam. 如果你按照我的建議去做，你一定不會(huì)(不可能)考試不及格。
3、表示與將來(lái)事實(shí)可能相反的假設(shè)和結(jié)果。如: If it were Sunday tomorrow, I should (would，could，might) go to see my grandmother. 如果明天是星期天，我就 (可能)去看望我奶 奶。If it were to snow this evening, they would not go out. 如果今晚下雪，他們將不出去了。
4、有時(shí)條件從句中的動(dòng)作和主句中的動(dòng)作發(fā)生的時(shí)間不一致（表示錯(cuò)綜時(shí)間的虛擬語(yǔ)氣），這時(shí)動(dòng)詞的形式要根據(jù)它所表示的時(shí)間加以調(diào)整。例如: If you had listened to the doctor, you would be all right now. 如果你當(dāng)初聽(tīng)了醫(yī)生的話(huà)，身體現(xiàn)在就好了。(從句動(dòng)作指過(guò)去，主句動(dòng)作指現(xiàn)在)
5、虛擬條件句可以轉(zhuǎn)換成下列形式:
(l)省略連詞if。在書(shū)面語(yǔ)中，如果虛擬條件從句中有were，had 或 should，可以把if省略，把這幾個(gè)詞放到主語(yǔ)之前，構(gòu)成主謂倒裝。例如: Should he come (If he should come), tell him to ring me up. 他要是來(lái)了，讓他給我打個(gè)電話(huà)。Were I you (If I were you), I would not do it. 我要是你，就不做這事。
(2)用介詞短語(yǔ)代替條件狀語(yǔ)從句。有時(shí)假設(shè)的情況并不用條件從句表示出來(lái)，而是通過(guò)介詞短語(yǔ)來(lái)表示。如: Without air (If there were not air), there would be no living things. 如果沒(méi)有空氣的話(huà)，就不會(huì)有生物了。But for your help (If it hadn’t been for your help) I couldn’t have done it. 要是沒(méi)有你的幫助，我就不可能完成這件事。
假設(shè)的情況有時(shí)可以通過(guò)上下文或其他方式表現(xiàn)出來(lái)。如: I was busy that day. Otherwise I would have gone there with them. (If I hadn’t been busy that day, I would have gone there with them.) 我那天很忙，否則，我就和他們一起去那兒了。(如果我那天不忙的話(huà)，我就……)；I would have finished the work, but I have been ill. (If I hadn’t been ill, I would have finished the work.) 我本來(lái)該完成這項(xiàng)工作的，但我生病了。(如果我沒(méi)生病的話(huà)，我就會(huì)完成……)
6、省去條件從句或主句：表示虛擬語(yǔ)氣的主句或從句有時(shí)可以省略，但其含義仍可以推知。
(1)省去條件從句。如: You could have washed your clothes yourself. 你本可以自已洗衣服的。省去了"If you had wanted to")(事實(shí)是:你自己沒(méi)洗衣服，因?yàn)槟悴幌胂础?
(2)省去主句(常用以表示愿望)。如: If my grandmother were with me! 如果我的祖母與我在一起多好啊!(事實(shí)是:祖母已不在世。)；If only she had not left! 如果她沒(méi)走就好了!(事實(shí)是:她已經(jīng)走了。)
三、虛擬語(yǔ)氣的其他用法
l、虛擬語(yǔ)氣在主語(yǔ)從句中的用法：在"It is important (strange，natural，necessary)that…"這類(lèi)句型里，that所引導(dǎo)的主語(yǔ)從句中的謂語(yǔ)動(dòng)詞常用 “should十動(dòng)詞原形”結(jié)構(gòu)，表示某事是"重要"、"奇怪"、"自然"、"必要"等意義。如: It is important that every member (should) inform himself of these rules. 重要的是每個(gè)成員知道這些規(guī)則。
2、虛擬語(yǔ)氣在賓語(yǔ)從句中用法：
(1)在動(dòng)詞wish后的賓語(yǔ)從句中，表示與現(xiàn)在或過(guò)去的事實(shí)相反，或?qū)?lái)的主觀愿望，從句通常省略連詞that。1)表示對(duì)現(xiàn)在情況的虛擬:從句動(dòng)詞用過(guò)去式或過(guò)去進(jìn)行式(be動(dòng)詞一般用were)。如: I wish I knew the answer to the question. 我希望知道這個(gè)問(wèn)題的答案。(可惜不知道)；2）表示對(duì)過(guò)去情況的虛擬:從句動(dòng)詞常用"had十過(guò)去分詞"。如: I wish (wished) I hadn’t spent so much money. 我后悔不該花那么多錢(qián)。(實(shí)際上已經(jīng)花掉)；3)表示對(duì)將來(lái)的主觀愿望:謂語(yǔ)動(dòng)詞形式為"would十動(dòng)詞原形"。此時(shí)要注意，主句的主語(yǔ)與從句的主語(yǔ)不能相同，因?yàn)橹骶涞闹髡Z(yǔ)所期望的從句動(dòng)作能否實(shí)現(xiàn)，取決于從句主語(yǔ)的態(tài)度或意愿(非動(dòng)物名詞除外)。如: I wish it would stop raining. 但愿雨能停止；I wish you would come soon. 但愿你立刻來(lái)。
(2)在suggest，demand，order，propose，insist，command，request，desire等動(dòng)詞后的賓語(yǔ)從句中，謂語(yǔ)動(dòng)詞用“should + 動(dòng)詞原形”，表示建議、要求、命令等。如: I demand that he (should) answer me immediately. 我要求他立刻答復(fù)我。
3、虛擬語(yǔ)氣在狀語(yǔ)從句中的用法
(1)在帶有even if/ even though引導(dǎo)的讓步狀語(yǔ)從句的主從復(fù)合句中，主句和從句都用虛擬語(yǔ)氣，動(dòng)詞形式與含有非真實(shí)條件句的虛擬語(yǔ)氣相同。如: Even if he had been ill, he would have gone t his office. 即使生了病，他倆去辦公室。
(2)由as if或as though引導(dǎo)的狀語(yǔ)從句表示比較或方式時(shí)。從句謂語(yǔ)形式為動(dòng)詞的過(guò)去式(be用were)或 “had十過(guò)去分詞”。如: He treated me as if I were a stranger. 他那樣對(duì)待我，好像我是陌
生人似的。She talked about the film as if she had really seen it. 她談?wù)撃遣坑捌�，就好像她確實(shí)看過(guò)一樣。
注:如果表示的事情可能會(huì)發(fā)生，那么方式狀語(yǔ)從句中的謂語(yǔ)動(dòng)詞可用陳述語(yǔ)氣。
(3)在in order that或so that引導(dǎo)的目的狀語(yǔ)從句中，謂語(yǔ)動(dòng)詞多用 “could或might（有時(shí)也用should）+ 動(dòng)詞原形”。如: Mr green spoke slowly so that his students could (might) hear clearly. 格林先生說(shuō)得很慢，好讓學(xué)生聽(tīng)清楚。
4、虛擬語(yǔ)氣在定語(yǔ)從句中的用法：在"It is time (that) …"句型中，定語(yǔ)從句的謂語(yǔ)動(dòng)詞常用虛擬語(yǔ)氣表示將來(lái)，動(dòng)詞形式一般用過(guò)去式，意思是"該干某事的時(shí)候了"。如: It’s (high) time we did our homework. 我們?cè)撟鲎鳂I(yè)了。
5、虛擬語(yǔ)氣在簡(jiǎn)單句中的用法
(1)情態(tài)動(dòng)詞的過(guò)去式用于現(xiàn)在時(shí)態(tài)時(shí)，表示說(shuō)話(huà)人的謙虛、客氣、有禮貌，或委婉的語(yǔ)氣，常見(jiàn)于日常會(huì)話(huà)中。如: It would be better for you not to stay up too late. 你最好別太晚睡覺(jué)。
(2)在一些習(xí)慣表達(dá)中。如: I would rather not tell you. 我寧愿不告訴你。
(3)用“may + 動(dòng)詞原形”表示"祝愿"、"但愿”，此時(shí)may須置于句首（多用于正式文體中）。如：May you be happy!祝你快樂(lè)！May good luck be yours.祝你順利。
練習(xí)、虛擬語(yǔ)氣
1. If I ____ where he lived, I ____ a note to him.
A. knew, would B. had known, would have sent
C. know, would send D. knew, would have sent
2. If they ____ earlier than expected, they ____ here now.
A. had started, would be B. started, might be
C. had started, would have been D. will start, might have been
3. I didn’t know his telephone number. ____ it, I ____ then.
A. Had I known, would ring him up B. Should I know, would have rung him up
C. If I knew; would ring him up D. Had I known; would have rung him up
4. Mary is ill today. If she _____ , she ____ absent from school.
A. were not ill; wouldn' t be B. had been ill; wouldn't have been
C. had been ill; should have been D. hadn't been ill; could be
5. Were I to do it, I ________ it some other way.
A. will do B. would do C. would have done D. were to do
6. I ________ him the answer ________ possible, but I was so busy then.
A. could tell; if it had been B. must have told; were it
C. should have told; had it been D. should have told; should it be
7. Without your help, we________ so much.
A. won ' t achieve B. didn ' t achieve
C. don't achieve D. wouldn't have achieved
8. You didn't take his advice. ________ his advice, you ________ such a mistake.
A. Had you taken; wouldn't have made B. If you had taken; would make
C. Were you lo take; shouldn t have made D. Have you taken; won t have made
9. We wish we ____ what you did when we were at high school.
A. did B. could have done C. have done D. should do
10. She wishes she ____ to the theatre last night.
A. went B. would go C. had gone D. were going
11. Tom is very short now. His mother wishes that he ________ be tall when he grows up.
A. could B. should C. would D. were able to
12. My sister advised me that I ________ accept the invitation.
A. could B. must C. should D. might
13. He asks that he ________ an opportunity to explain why he’s refused to go there.
A. is given B. must give C. should give D. be given
14. Do you think of Wang Fang's suggestion that he ________ Mr. Li to the party?
A. will invite B. have invited C. is invited D. invite
15. I insisted that he ________ at once.
A. be gone B. go C. would go D. might go
16. Li Ming insisted that he ________ anything at all.
A. hadn ' t stolen B. shouldn ' t steal C. doesn ' t steal D. steal
17. It is quite natural that my coming late again ________ them very angry.
A. had made B. would make C. makes D. make
18. He acted as if he ________ everything in the world.
A. knew B. knows C. has known D. won't know
19. Read it aloud so that I ________ you clearly.
A. may hear B. will hear C. hear D. have heard
20. They got up early in order that they ________ they first train.
A. caught B. will catch C. might catch D. shall catch
21. I am sorry that he ________ in such poor health.
A. are B. shall be C. were D. should be
22. That is a good book. You ________ it yesterday.
A. could buy B. should buy C. should have bought D. bought
23. It is high time we ________ home.
A. will go B. would go C. have gone D. went
24. I ' d rather that you ________ home.
A. went B. have gone C. will go D. had gone
25. If only I _________ to the lecture!
A. listen B. will listen C. am listening D. had listened
26. ---- If he_____ , he ______ that food. ---- Luckily he was sent to the hospital immediately.
A. was warned; would not take B. had been warned; would not have taken
C. would be warned; had not taken D. would have been warned; had not taken
27.I didn' t see your sister at the meeting. If she _________, she would have met my brother.
A. has come B. did come C. came D. had come
28. Without electricity, human life ________ quite different today.
A. is B. will be C. would have been D. would be
29. He ________ you more help, even though he was very busy.
A. might have given B. might give C. may have given D. may give
30. If city noises _______ from increasing, people _______ shout to be heard even at the dinner table 20 years from now.
A. are not kept; will have to B. are not kept; have to
C. do not keep; will have to D. do not keep; have to
31. Mike's father, as well as his mother, insisted that he ________ home.
A. stayed B. could stay C. has stayed D. stay
32. Mr. Smith insisted that he ________ the work all.
A. had done B. have done C. did D. so
33. Jane would never have gone to the party ________ that Mary would come to see her.
A. has she known B. had she known C'. if she know D. if she has known
34. If you had enough money, what ________ ?
A. will you buy B. would you buy C. would you have bought D. will you have bought
35. If you ________ that film late last night, you wouldn't be so sleepy.
A. didn't see B. haven't seen C. wouldn’t have seen D. hadn’t seen
36. Our monitor requested that ________.
A. all the class studied more carefully the problem
B. the problem was more carefully studied
C. with great care the problem could be studied
D. all the class study the problem more carefully
37. ---- Would you have called her up had it been possible?
---- Yes, but I ________. busy doing my homework..
A. was B. were C. had been D. would be
38. His tired face suggested that he ________ really tired after the long walk.
A. had been B. was C. be D. should be
39. It is important that we ________.
A. shall close the window before we leave B. will close the window before we leave
C. must close the window before we leave D. close the window before we leave
40. I didn't know his telephone number, otherwise I ______ him.
A. had telephoned B. would telephone C. would have telephoned D. telephone