一直以来，英语是很多人想要去学习但是就是学不动的一门学科，包括的高中生以及大学生。事实上，要想学好英语其实并不难，首先要背诵精彩的英文句型，只要把句型基础打好了，阅读理解学起来就会不少。下面，小编就给考生们整理了高中英语语法中的表语从句，希望对大家有所帮助。

　　1.定义：用作表语的从句叫做表语从句。

　　2.构成：关联词+简单句

　　3.引导表语从句的关联词的种类：(1)从属连词that。如：The trouble is that I have lost his address.麻烦是我把他的地址丢了。(2)从属连词whether,as,as if。如：He looked just as he had looked ten years before.他看起来还与十年前一样。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 it's as if it was only yesterday.这都是20多年前的事了，但宛如昨天一样。能跟表语从句的谓语动词一般为系动词be,seem,look等。如：It looked as if it was going to rain.看起来天要下雨了。(3)连接代词who,whom,whose,what,which,whoever,whatever,whichever 连接副词 where,when,how,why。如：The problem is who we can get to replace her.问题是我们能找到谁去替换她呢。The question is how he did it.问题是他是如何做此事的。That was what she did this morning on reaching the attic.那就是她今晨上了阁楼干的。

　　解释：1.连词because可引导表语从句。如：I think it is because you are doing too much.我想这是因为你做得太多。2.在一些表示“建议、劝说、命令”的名词后面的表语从句中，谓语动词用虚拟语气。should+动词原形表示，should可省略。如：My suggestion is that we (should)start early tomorrow.我的建议是我们明天一早就出发。