全國(guó)英語(yǔ)等級(jí)考試三級(jí)語(yǔ)法知識(shí)點(diǎn)：虛擬語(yǔ)氣

虛擬語(yǔ)氣表示說(shuō)話(huà)人的主觀(guān)愿望、猜疑、建議或與事實(shí)不符的假設(shè)等，而不表示客觀(guān)存在的事實(shí)。虛擬語(yǔ)氣是由句中的謂語(yǔ)動(dòng)詞的特殊形式表示出來(lái)的。如：

If I were a bird，I would be able to fly in the air.如果我是一只小鳥(niǎo)，我就能在空中飛行。

I wish I could pass the examination.我希望我能通過(guò)考試。

1、普通型虛擬語(yǔ)氣主句與從句動(dòng)詞虛擬形式的搭配如下：

與現(xiàn)在事實(shí)相反：從句為過(guò)去式(be一般were)，主句為would／should+動(dòng)詞原形；

例：If he studied harder，he might pass the exam（如果他努力學(xué)習(xí)，他可能通過(guò)考試了）

不論主語(yǔ)為第幾人稱(chēng)，if從句中的be動(dòng)詞均用were；主句中的助動(dòng)詞一定為過(guò)去時(shí)，且后面接動(dòng)詞原形

例1：If I were you ，I would beat him

例2：If he were here，I would beat him

與將來(lái)事實(shí)相反：從句為should+動(dòng)詞原形，主句為wonld／should+動(dòng)詞原形；

例：If it should rain，the game would be put off（如果下雨，比賽會(huì)推遲）

使用要點(diǎn)：if從句一定要加助動(dòng)詞should，if……should翻譯為“萬(wàn)一”；

與過(guò)去事實(shí)相反：從句為had+過(guò)去分詞，主句為would／should+have+過(guò)去分詞。用此句型時(shí)從句中會(huì)出現(xiàn)had had 的情況，同學(xué)們要注意區(qū)分had與had had區(qū)別

例1：If he had money，he would buy a car.

（如果他有錢(qián)，他會(huì)買(mǎi)輛車(chē)）此句中had為一般過(guò)去時(shí)動(dòng)詞，翻譯為“有”

例2：If he had had money，he would have bought a car

（如果他那時(shí)有錢(qián)，他就會(huì)買(mǎi)輛車(chē)）此句中第一個(gè)had為過(guò)去完成時(shí)助動(dòng)詞，第二個(gè)had為have（有）的過(guò)去分詞。

2、 表示與真理相反的虛擬語(yǔ)氣的結(jié)構(gòu)

從句：if + 主語(yǔ) + were to do,

主句：主語(yǔ) + should/would/could/might/ought to

真理：The sun dose't rise in the west

假設(shè)：If the sun were to rise in the west，how surprised people would be（如果太陽(yáng)從西邊升起，人們會(huì)多么吃驚?。?/p>

3、在虛擬語(yǔ)氣的if從句中，若有過(guò)去完成時(shí)助動(dòng)詞had,或表“萬(wàn)一”的should或是were出現(xiàn)時(shí)，可將這三個(gè)詞提前，將if省略

should it rain（if it should rain），the game would be put off. 

萬(wàn)一下雨，比賽就會(huì)推遲

Had he done it（if he had done it），he would have felt sorry.

如果他當(dāng)時(shí)做了這件事，他會(huì)后悔的