as if (as though)若表示与现在事实相反，谓语动词用一般过去时;若表示与过去事实相反，用过去完成时;表示将来的可能性不大，用would (might, could)+动词原形。

as if和as though的虚拟语气的用法

它的常规用法相信同学们都很熟悉，今天牛津英语要跟大家强调两点罕见情况。

(1) 从句所表示的内容若为事实或可能为事实，也可用陈述语气：

It looks as if we'll be late. 我们似乎要迟到了。

This meat tastes as if it has already gone bad. 这肉吃起来似乎已经坏了。

在现代英语中，有时即使从句内容不是事实，也可能用陈述语气：

I feel as if [as though] I'm floating on air. 他感到好像漂浮在空中。

The stuffed dog barked as if it is [were, was] a real one. 玩具狗叫起来像真狗。

(2) 注意 It isn't as if…的翻译：

It isn't as if he were poor. 他不像穷的样子(或他又不穷)。

It isn't as if you were going away for good. 又不是你离开不回来了。