It was exactly what I needed
That's when I decided.
两句都是表语从句.
表语从句
在句子中起表语作用的从句叫做表语从句.表语从句的引导词和主语从句的引导词相同.
What the police want to know is when you entered 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.