但除了名词以外还可以用代词、动名词、不定式短语，名词性从句、名词短语、表距离的地点副词短语等做主语。
1、名词作主语。
The child is my daughter.
2、代词做主语。
He always keeps his promise.
3、动名词或不定式短语作主语。
动词一定一定不能做主语，要变成动名词或者不定式短语，如此才能和名词对等。
Seeing her makes me angry.
To see him is my purpose of coming here.
4、名词性从句做主语
A.主语从句（作主语）：That the earth is round is true.
5、名词短语作主语
名词短语由“疑问词 ＋ 不定式短语”形成
① 疑问副词
Where to live
Whether to try again
When to talk to him
How to do it
例1. Where to live is still unknown.
例2. Whether to try again is still not decided
② 疑问代词
What to do
Whom to see
Which to by
例.which to buy depends on how much money do you have.
6、表距离的地点副词短语做主语
From + 地点 + to + 地点
例.from shanghai to Beijing is about 1000 kilometers.
引导词that和which的区别
that代表那个，which，who代表多个中的一个。
所表示的事物只有一个或是对这个事物的指向已经非常明显了，并没有“从多个中选一个”的暗示在里面，所以引导词只能用that。
that从句不可做介词的宾语，只能用whether 从句或疑问词引导的从句
例1. I am worried about whether he can do it.
那如果硬要用that从句怎么办呢？且请看
① 在介词之后加the fact ,结构为：介词+ the fact+ that从句例：I am worried about the fact that he doesn’t study.