英語四級語法虛擬語氣詳解

英語四級語法虛擬語氣是經常考的內容，所以大家在備考的過程中一定要掌握。下面是小編給大家分享的四級語法知識，大家可以作爲學習的參考。

1. if 引導的虛擬語氣

a. 指現在的事： 前面用were/過去式，後面用 should (would) +動詞原形

例句 If he were here, he would help you now.

b. 指過去的事： 前面用過去完成時，後面用 should (would) have+ 過去分詞

例句 If she had worked harder, she would have succeeded.

If he had come yesterday, I should / would have told him about it.

If he had not been ill and missed many classes, he would have made greater progress.

c. 指將來的事： 前面用were/過去式，後面用 should+ 動詞原形

或前面用 were+ 不定式，後面用 would + 動詞原形

或前面用 should+ 動詞原形，後面用 would + 動詞原形

例句 If you succeeded, everything would be all right.

If you were to succeed, everything would be all right.

If you should succeed, everything would be all right.

2. 倒裝形式

Were I you (=if I were you) , I would get up early in the morning.

Had you arrived at the station ten minutes earlier yesterday(=If you had arrived…), you could have caught the train.

Should it rain (=If it should rain), the crops would be saved.

3、固定句型

“It is (was)+形容詞(或過去分詞)+that……”結構中的虛擬語氣

It is necessary that we (should 可省略,下同)have a walk now.

It was necessary that we (should) make everything ready ahead of time.

4、名詞性從句中要用過去時或should+動詞原型構成虛擬語氣。如：It is time we went home.

5、would rather,had rather後的從句動詞用相當於陳述語氣的過去時來表示現在或將來發生的動作。

如：I would rather you went with her.我寧願你跟她走。

只有當would rather後面動作的主體與前面主語一致時纔可以用不帶 to的動詞不定式，

如：I’d rather take the important letter with me.