一日一句【68】what和that、which比较

what 和that、which比较：

示例：
What I need now is to lie down and have a good rest.
我现在需要的是躺下来，好好地休息一会儿。

关系代词what与that或which不同。that与which通常代替前面的名词，并“重复其意思”：

I gave her the present which she asked for.
我给了她所要的礼物。（在此句中which代表了present）

而what 的含义则是the thing(s) that，故上句可写为：

I gave her what she asked for. (what = the present which)

what作关系代词时相当于the thing which或the thing that，故应当接一个单数形式的动词。

What we need is more motorways.
我们所需要的是更多的公路。