I found it very interesting to study English.

　He made it clear that he was not interested in this subject.

II I..用于强调结构

要强调句子的某一部分, 通常是主语、状语、宾语, 可以把it当作先行词。这种句子的结构是：

"It is/was+被强调部分+that/who+句子的其他部分"。如果强调的是人,可以用who, whom代替that。

e.g. I met Tom in the street yesterday．

① It was I who (that) met Tom in the street yesterday.

② It was Tom that I met in the street yesterday.

③ It was in the street that I met Tom yesterday.

④ It was yesterday that I met Tom in the street.

It的一些习惯用法

　How is it with your study?

　That's it. 这就对了。

　It went hard with him. 他身遇不幸。

　It is all over with me. 我完蛋了。

We must fight it out. 我们必须坚持到底。

I can't help it. 我没有办法。

口诀：

代词 it 本意它, 既可指这又指那;

时间天气均可指, 谈到距离也用它;