This is what I want,这就是我想要的 The reason why he was late is that his bike broke down. 他迟到是因为自行车坏了 Next sunday is when we shall meet. 下周日是我们见面的时间 This is why I am late.这就是我迟到的原因 My problem is which computer to choose 我的问题是不知道选哪个电脑好 The argument is whether it rains tomorrow 明天是否下雨是争论的内容
What the police want to know is when you entered red the room警察想知道的是你什么时候进的房间。
The trouble is that we are short of funds困难是我们缺乏资金。
This is what we should do这是我们应当做的。
That‘s why I want you to work there那就是我要你在那儿工作的原因。
His first question was whether Mr. Smith had arrived yet他的第一个问题是史密斯先生到了没有。
注意：从句中的疑问句用正常语序，即陈述语序。
as if,as though,because也可用来引导表语从句。
She seems as if she had done a great thing她看起来好像做了一件大事。
It is because you eat too much是因为你吃得太多了。
The fact is that he doesn’t really try. 事实是他没有做真正的努力。
The trouble is that I have lost his address. 麻烦的是我把他的地址丢了。
My suggestion is that we should tell him. 我的建议是我们应该告诉他
2. 由whether引导
The question is whether the film is worth seeing. 问题是这部电影是否值得看。
3. 由连接代词引导
You are not who I thought you were. 你已不是我过去所想像的人。
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 who (m) we should trust. 问题是我们应当相信谁。
What I want to know is which road we should take. 我想知道的是我们应走哪条路。
4. 由连接副词引导
The problem is how we can find him. 问题是我们如何找到他。
That was when I was fifteen. 这是我15岁时发生的事。
That’s where I first met her. 那就是我第一次遇见她的地方。
That’s why he didn’t come. 这就是他没有来的缘故。
That’s why I object to the plan. 这就是我反对这个计划的原因。
That’s where you are wrong. 这就是你不对的地方。
5. 由关系代词型what引导
That’s what I want to stress. 这是我想强调的。
That’s what we are here for. 我们来这里就为了这个。
Fame and personal gain is what they’re after. 他们追求的是名利。
He is no longer what he was. 他已经不是以前的他了。
6. 由as if / as though引导
It isn’t as if you were going away for ever. 又不是你离开不回来了。
Now it was as though she had known Millie for years. 现在好像她认识米莉已有好多年了似的。
It is not as though we were poor. 又不是我们家里穷。本回答被网友采纳
表语从句（Predicative Clause）就是用一个句子作为表语。说明主语是什么，由名词、形容词或相当于名词或形容词的词或短语充当表语的成分。
表语从句定义：在一个复合句中，从句作的是主句的表语成分。
A
The problem is puzzling.
这个问题令人困惑。
主语+连系动词+形容词作表语
The problem is when we can get a pay rise.
问题是什么时候我们可以得到加薪。
主语+连系动词+句子作表语（表语从句）
B
连接表语从句的连接词有：that, what, who, when, where, which, why, whether, how, whoever，whichever ，whatever等。还有如because, as if, as though等。
His suggestion is that we should stay calm.
他的建议是，我们应该保持冷静。
The question is when he can arrive at the hotel.
问题是，他什么时候可以到达酒店。
My question is when / where he will go.
That is how he did it.
That is what he said.
My question who will be sent there.
That beautiful pair of Timberland boots, which I had worn for 10 years, was given to me by my sister-in-law.
这就是从句，一层叠一层。
That beautiful pair of Timberland boots, which I had worn for 10 years, was given to me by my sister-in-law.
以上黑体的分别是主语、动词及宾语。