表语从句位于主句的连系动词之后，在非正式文体中引导词that可以省略。如：

That’s not what I want. 那不是我要的。

That’s why I have come. 那就是我为什么来了。

My opinion is that things will improve. 我的意见是事情会好起来的。

One advantage of solar energy is that it will never run out. 太阳能的一个优点是永远也不会枯竭。

The truth is that he didn’t really try. 实际情况是他没有真正努力。

The problem is who is to pay and when we can start. 问题是谁来付帐、我们又何时开始。

The fact is that he didn’t notice the car until too late. 事实是他注意到车时已经太晚了。

What surprised me was that he spoke English so well. 使我感到吃惊的是他英语讲得那么好。

All I can say is that I have nothing to do with it. 我能说的就是我与此事没有关系。

What I want to know is where we shall go and whether she will join us. 我想知道的是我们要去什么地方以及她是否加入我们。

The fact is that he didn’t notice the car until too late. 事实是他注意到车时已经太晚了。

What surprised me was that he spoke English so well. 使我感到吃惊的是他英语讲得那么好。

All I can say is that I have nothing to do with it. 我能说的就是我与此事没有关系。

What I want to know is where we shall go and whether she will join us. 我想知道的是我们要去什么地方以及她是否加入我们。

此外，表语从句还可由as if (好像)引导。如：

It looked as if it was/were going to rain. (虚拟语气) 看起来好像要下雨了。

翻译练习：

这就是她昨天请一天假的原因。

That is why she had a day off yesterday.

我的想法是，个人的权利应该得到充分尊重。

My idea is that individual rights should be fully respected.

问题在于上帝是否真的存在。

The question is whether the God really exists.

我想知道的是，他是如何在这么短的时间内完成这个项目的。

What I want to know is how he managed to complete the project in such a short time.