as if连接的从句，既可表示对现在、将来时间的虚拟，又可以是对过去时间的虚拟。当在虚拟语气中，as if用来表示与现在事实相反的情况，其从句应该用一般过去时。

虚拟语气as if的三种用法是什么

1、用于表示与现在事实相反的情况。

当在虚拟语气中，as if用来表示与现在事实相反的情况，其从句应该用一般过去时，不过在虚拟语气中，be动词要用were，就算主语是单数，也用were。

例句：

The rest of the application should continue as if nothing happened.

程序其它部份应该可以继续像往常一样运行。

2、用于表示与过去事实相反的情况。其中，从句的结构是主语+had+动词的过去分词。

当as if用于表示与过去事实相反的情况，其从句的结构为主语+had+动词的过去分词形式。

例子：

I suggest that you should stay here as if nothing had happened.

我建议你应该呆在这儿，好像什么事情都没发生。

3、用于表示与将来事实相反。

当as if用于表示与将来事实相反，其从句的结构为主语+would/could/might/should+动词原形。

例句如下：

The lady brisked up to him as if she would fight him.

那妇人向他急急而来，好像要跟他动武似的。

as的固定搭配短语

as well as 也;和....一样好;

as long as 只要;长达....之久;

as tall as 和....一样高;

as big as 和....一样大;

as wide as 和....一样宽;

as deep as 和....一样深;

as much as 和....一样多;高达

as far as 远至 ; 就……而言 ; 远到 ; 就;

as clear as day 一清二楚的 ; 明若观火 ; 了如观火 ; 显而易见;

as good as 和…几乎一样 ; 几乎已经 ; 和 ; 不亚于;

as for as 就…而论;

As Early As Possible 尽早 ; 趁早 ; 早早儿 ; 尽快地;