请问it的用法有哪些？帮我列出来谢了。看书没看懂

It 用法小结虽不是高考的热点，但这两年全国各省市试题经常出现。我们不能疏忽。 下面是用法20条。 并通过高考试题进行巩固：

1.It is+被强调部分+that

该句型是强调句型，将被强调的放在前面，其他部分置于之后，强调的主语如果是人，可以用来替换，如果把这种句型结构划掉后，应该是一个完整无缺的句子，这也是判断强调句型与其他从句的方法。

It was they that (who) cleaned the classroom yesterday. It was in the street that I met her father.

It was with great joy ___he received the news that his lost daughter had been found. (2004 福建)

A. because B. which C. since D. that (D)

2. It is not until +被强调的部分+ that

该句型译成汉语“直到……才”，可以说是的强调形式。It was not until she took off her dark glasses that I realized she was a film star. =Not until she took off her dark glasses did I realize she was a film star. =I didn’t realize she was a famous film star until she took off her dark glasses.

It was ___back home after the experiment. (2004 湖北)

A. not until midnight did he go

B. until midnight that he didn’t go

C. not until midnight that he