六、虚拟语气在as if/as though引导的状语从句和表语从句中的用法

我们在学习as if/as though所引导的表语从句和状语从句时，往往把它们与虚拟语气在if条件句中的用法混淆起来。if条件句的虚拟语气动词形式是以说话时的时间为参照点，分为与现在相反、与过去相反和与将来相反三种情况;而as if/as though从句是根据从句的动作与主句的动作的先后来确定。即我们在确定as if/as though从句的谓语动词形式时，不要考虑主句的时态是什么，而要看从句的动作是发生在主句动作的同时、之前还是之后。这样说来，无论主句的时态如何，as if/as though从句的动词形式有三种可能:(1)从句和主句同时发生，从句用过去式;(2)从句发生在主句前，从句用had done;(3)从句发生在主句后，从句用“would+不定式”或“was/were going to”。这种用法与wish宾语从句的形式有些类似。

It looked as if the creature had moved．(人教大纲版高一上第83页)

塑像好像动了动。

John acts/acted as if he didn't know the thing at all，but in fact he knows/knew it very well．

他表现得好像对此事一无所知，事实上他非常了解。

The old man looked/is looking at the picture，he felt/feels as though he had gone back to time 20 years/before ago．

老人看着照片，感觉就好像回到了20年前。

It looked as if she were dead．(人教大纲版高二上第59页)

他看上去就像死了一般。

With a tearing crash，tons of water fell upon the deck，as though the ship passed under a waterfall．

(人教大纲版高二上第79页)

随着一阵撕裂般的哗啦声，成吨的海水泼向甲板，仿佛轮船驶过了瀑布。

They talked and talked/are talking and talking as if they would never meet again．

他们不停地交谈，就像再也不会见面了似的。

Seems as if the wind had dropped，Sir．(人教大纲版高二上第79页)

似乎风力下降了，长官。

Most exchange students say that they feel as if they were truly part of their host families．(人教大纲版高三第71页)

大多数交流学生说，他们觉得自己真的像主人的家庭成员一样。

提示：

一般而论，如果as if/as though从句所表达的内容完全与实际情况相反或者纯粹是一种假设时，通常使用虚拟语气。

He looked as though he were from the country．

看上去他是从农村来的。

It seems as if he were drunk．

他似乎是喝醉了。

It looked as if it were broken．(人教大纲版高二下第134页)

看上去(他的腿)像是断了。

He looked as if he had just stepped out of my book of fairy tales and had passed me like a spirit．

他(爱因斯坦)看上去好像刚从我的童话故事书中走了出来，像幽灵一样从我身旁闪过。

但是as if/as though引导的表语从句中并不强制使用虚拟语气，如果as if/as though从句所表达的内容被看作是事实或者可能是真实的，就要使用陈述语气。请对比:

但是也有特殊情况，如果从上下文或句意可以明显地看出as if从句所表达的内容是非真实的，as if/though从句使用陈述语气或使用虚拟语气没有什么差别。

Seen from the top，it looks as if the stadium is covered by a gray net of steel．(人教大纲版高二上第20页)

从顶上看，仿佛体育场覆盖着灰色的钢网。(很显然不是。)

She treats me as if I'm/I were a stranger．

她对待我的态度就好像我是陌生人似的。(两个句子都意味着“我并不是一个陌生人”。)

He talks as if he knows/knew everything．

他说起话来就好像什么都懂似的。(语义明显看出任何一个人不可能什么都懂。)

He talks as if he has/had a potato in his mouth．

他说起话来好像嘴里含着一个土豆似的。

The stuffed dog barks as if it is a real one．

这只玩具狗叫起来好像真狗似的。