as if / as though 从句用虚拟语气的格式
以as if (as though)引导的方式状语从句或表语从句，有时用虚拟语气，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。如：
I love you as if you were my son. 我爱你就像你是我的儿子。
When a pencil is partly in a glass of water, it looks as if it were broken. 当把一支铅笔的一部分放在一杯水里时, 它看起来好像折断了似的。
注：有时虚拟语气并不明显(特别是主句动词为过去时时)。如：
He paused as though he found a difficulty. 他停了下来，仿佛遇到什么困难似的。
若从句所表示的内容为事实或可能为事实，也可用陈述语气。如：
It seemed as though he didn't recognize me. 他似乎没认出我来。
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。
另外，注意 It isn’t as if…的翻译。如：
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。
