虛擬語(yǔ)氣是一種動(dòng)詞形式，表示說(shuō)話(huà)人的一種愿望，假設，懷疑，建議等含義，虛擬語(yǔ)氣所表示的含義不是客觀(guān)存在的。

一．在非真實(shí)條件句中

虛擬條件句（if從句） 主句

與現在事實(shí)

相反 主語(yǔ) + 主語(yǔ) + would/could/might/ should + do

與過(guò)去事實(shí)

相反 主語(yǔ) + 主語(yǔ) + would/could/might/should + have done

與將來(lái)事實(shí)

相反 ①主語(yǔ) + did

②主語(yǔ) +were to do

③主語(yǔ) + should do 主語(yǔ) + would/could/might/should + do

1 If I were you, I would buy it. 2 If she knew English, she would ask me for help now.

3 If you had got up earlier, you would have caught the train yesterday.

注意：錯綜時(shí)間條件句：從句和主句發(fā)生的時(shí)間不一致時(shí)，動(dòng)詞的形式要分別根據它所表示的不同時(shí)間作相應的調整。 5 If you had followed my advice (聽(tīng)從)yesterday, you would be better now.

6 If they had studied hard in the past, they would do it easily now.

二 省略if的情況: 虛擬條件句中含were , should, had 時(shí)，可省略if,把這幾個(gè)詞置于句首。

1 Were I you, I wouldn’t do that. （be） 2. Had you come earlier, you would have seen him.

3. Should it rain tomorrow, I would stay at home.

三 含蓄條件句 :使用with, without, but, or,or else, otherwise， but for(= if it were not for…與現在事實(shí)相反；if it had not been for…與過(guò)去事實(shí)相反)等代條件句。

1 We couldn’t have succeeded without your help.(沒(méi)有你的幫助)

2 But for the rain（要不是） we would have finished the work.

3 He telephoned to inform me of your birthday. or (=If he hadn’t telephoned to inform me of your birthday)I would have known nothing about it.

但是： If it were not for the fact that she ____sing, I would invite her to the party. C

A. couldn’t B. shouldn’t C. can’t D. mightn’t

四 常用虛擬語(yǔ)氣的句型

(一) 在下列句型中，常用“should + 動(dòng)詞原形”且should可以省略：

1 表示要求，建議，命令，提議，意愿等的主語(yǔ)從句，賓語(yǔ)從句，表語(yǔ)從句和同位語(yǔ)從句中。

一堅持insist; 二命令order, command; 三建議suggest, advise,propose; 四要求demand,require,request,ask等后。

注意：當suggest作__________講，insist作_________講，后邊that從句不用虛擬語(yǔ)氣。

2 在It is + 形容詞(necessary, natural, strange, etc. ) + that從句中。

在It is/was a pity（a shame, no wonder, etc. ） + that從句中。

1）We all agreed to his suggestion（that）we (should abandon the plan. 放棄那個(gè)計劃.

2) It is suggested that the meeting should be put off next week.（被推遲）

3) It’s necessary/important/natural that we_______________________每天打掃房間.

但是1) Mike insisted that he had never stolen anything. （從未偷過(guò)）

2) The look on his face suggested that he was angry.

但是： It is（high/about）time（that）sb.did sth /should do sth

Eg: It is high time we started / should start. 動(dòng)身出發(fā)

(二) 用動(dòng)詞的過(guò)去式表示與現在事實(shí)（或將來(lái)事實(shí)）相反，用動(dòng)詞的過(guò)去完成式表示與過(guò)去事實(shí)相反的句型。

1)．wish后that引導的賓語(yǔ)從句中。(表示對將來(lái)的設想，用could/would/might+v.)

2)．a(chǎn)s if（though）引導的表語(yǔ)從句或方式狀語(yǔ)從句中。

3)．would rather后的賓語(yǔ)從句中。

4)．If only引導的感嘆句中。

1 I wish I _______________________. 和你一樣聰明。

2 I wish he ______________________ tomorrow. 再次嘗試

3 He looks as if/though he ____________________. 他是一個(gè)藝術(shù)家

4 I’d rather you _________________ there yesterday. 不去

5 Look at the terrible situation I am in! If only I _______________ (follow) your advice.