虛擬語氣

1. 表示現在/過去/將來情況的虛擬條件句

虛擬條件句主要有三種結構：

1）表示與現在情況相反：主句謂語用“would / could / might +動詞原形”，從句謂語用“動詞的一般過去時”（動詞be的過去式一律用were）。

If I were you， I would not accept his offer.

If I had time， I would certainly go to the cinema with you.

2） 表示與過去情況相反：主句謂語用“would / could / might + have +過去分詞”，從句謂語用過去完成時。

If I had got up a little earlier， I wouldn’t have missed the train.

If I had been more careful， I might have passed that exam.

3） 表示與將來情況相反：主句謂語用“would / could / might +動詞原形”，從句謂語用“were +動詞不定式”或“should +動詞原形”。

If I were to do the job， I would not be able to have enough time to study.

If it should rain tomorrow， I would not go out with you.

2. 虛擬條件句連接詞if的省略

如果虛擬條件句的從句中含有were， had， should， could等詞時，可以省略連接詞if，但這時必須把were， had， should， could等詞移到主語前面，形成倒裝。這種句型主要用于書面形式。

Were I to do the job， I would finish doing it within two weeks.

Had it not been for his help， we couldn’t have arrived there on time.

Should it rain tomorrow， I would stay at home.