5. 关系代词型what引导
What we need is money. 我们需要的是钱。
What I want to know is this. 我想知道的就是这一点。
What’s done is done. 事已成定局。
What he says is not important. 他说的话并不重要。
What I am telling you is mere impressions. 我和你说的都不过是一些印象而已。
What make the river more beautiful are the lotus plants growing in the water. 为河水增色的是水里的荷花。
What you need is a good-sized canvas bag. 你需要的是一个比较大的帆布袋。
What I am afraid of is their taking him to Portugal. 我担心的是他们把他带到葡萄牙去。
What struck me was that they have all suffered a lot. 给我很深印象的是他们都受过很多苦。
二、主语从句与形式主语it
有时为了考虑句子平衡，通常在主语从句处使用形式主语it，而将真正的主语从句移至句末。这分三种情况：
(1) 对于以连词that引导的主语从句，通常用形式主语代主语从句：
It’s a pity that he didn’t come. 很遗憾他没来。
It is important that he should know about this. 他必须知道此事。
It’s vital that we be present. 我们出席是至关重要的。
It was intended that you be the candidate. 大家的意图是让你当候选人。
It is important that this mission not fail. 这项使命不失败至关重要。
It is essential that a meeting be convened this week. 本周开一次会非常重要。
It is appropriate that this tax be abolished. 废除这个税是恰当的。
It’s unfair that so many people should lose their jobs. 竟有这么多人失业这是不公平的。
It’s amazing that she should have said nothing about it. 她竟未谈及此事令人惊讶。
It’s unthinkable that they should deny my request. 他们竟然拒绝我的请求，这是不可思议的。
That they should refuse to sign the petition required great courage. 他们拒绝在请愿书上签字这是需要很大勇气的。
(2) 对于以连接代词(副词)引导的主语从句，可以使用形式主语代主语从句，也可直接在句首使用主语从句：
Whether they would support us was a problem. 他们是否会支持我们还是一个问题。
It was a problem whether they would support us. 他们是否会支持我们还是一个问题。
It remains to be seen whether it will do us harm or good. 它对我们是利是害，还得看看再说。