Ⅰ.虚拟语气

表示所说的不是事实，或者是不可能发生的情况，而只是一种愿望、假设或猜测。

1.表示和现在事实相反的假设：

He is honest. If he were dishonest, I should not trust him.

He is not alive. If he were alive today, he would be a hero.

2.表示和过去事实相反的假设：

If there had been no air, there would have been no living things.

You didn't come here yesterday. If you had come here yesterday, you would have seen him.

3.和将来事实相反的假设：

If he should be here tomorrow, he would call me up.

If it were to rain tomorrow, the match would be cancelled.

4.虚拟语气的一些其他用法

(1)在动词require, propose, recommend, suggest, demand, insist 和order等后面的宾语从句中，一般用虚拟语气.

例如：

I suggest that we (should) repair the machine at once.

The leader of the team ordered that all (should) finish the work by supper time.

He insisted that all (should) attend the meeting.

(2)在“It is time(that) +从句”的结构中，从句的谓语动词用过去式.

例如：It is time we went to work.

(3)在由as if, so that, in order that, as though等引导的状语从句中，也往往用虚拟语气形式。

例如: Annie treated me exactly as if I were a seeing and hearing child.

(4)虚拟语气在主语从句中的用法：在It is necessary (natural, strange, important) that等句型中，后面主语从句的谓语动词要用“should+动词原形”结构。本文|由职业培训教育网独家整理。

例如：

It is strange that he should have been late for the meeting.

It is necessary that we should take the box away at once.