.表语从句1 定义：用作表语的从句叫做表语从句。2 关联词(1) 从属连词that。在从句中不做成分。如：The trouble is that I have lost his address.麻烦是我把他的地址丢了。 The reason was that he was late for school.(2) 从属连词whether, as, as if。如：1. He looked just as he had looked ten years before.他看起来还与十年前一样。2. The question is whether they will be able to help us. 问题是他们是否能帮我们。注：从属连词if一般不用来引导表语从句，但as if却可引导表语从句，如：All this was over twenty years ago, but its as if it was only yesterday.这都是20多年前的事
