it 的用法总结
it的用法及其句型和固定搭配，是英语语法的重点，也是近几年考试的热点，因此同学们在学习时应给予足够的重视。现在我们将it的用法归纳如下：
请观察以下句子，看看各句中的it各指代什么，有何共同特征？
1. Life is like a fire; it begins in smoke, and ends in ashes.
2. She didn’t come yesterday, and it meant that she was angry.
3. I can’t believe it !
4. —Who is knocking at the door? —It’s me.
5. It is rather windy at sea sometimes.
6. It is thousands of miles from Gambia to America.
7. It was midnight when he heard a man crying softly.
8. It is never too late to mend.
9. It is no use talking to them.
10. It is said that he stole the money.
11. I think it difficult to learn English well.
12. We make it clear that speaking to the teacher in that way is not polite.
13. I don’t like it when people talk with the mouth full of food.
14. It was in the street that I met her father.
15. It was not until she took off her dark glasses that I realized she was a famous film star.
用法归纳：
一．用作人称代词，代替前文提到过的事物。如:
The train has arrived. It arrived half an hour ago.
二. 用以代替指示代词this, that。如:
—Whose watch is that? —It’s mine.
三. 起指示代词的作用，指一个人或事物。如:
—Who is knocking at the door? —It’s me.
四. 指环境、情况等。如:
It was very noisy (quiet) at the very moment.
五. 指时间、季节等。如:
—What time is it? —It’s eight o’clock.
六. 指距离。如:
It is only five miles from here to the hospital.
七. 指自然现象（天气、气候、明暗等）。如:
1. It is + 形容词(+ of sb.) + to do sth.。
形容词必须是能表示逻辑主语sb.特征的形容词。常见的有: bad, brave, careless, clever, cruel, foolish, , honest, horrible, kind, lazy, modest, naughty, , polite, rude, silly, stupid, wise,等。
Eg: It is brave of her to go home alone at night.
2. It is + 形容词( for sb. ) to do sth.
该句型与上一个同属一个句型。形容词通常表示某事的重要性，紧迫性，难易，安全等情况。常见的形容词有：①important, necessary, natural ②easy, safe, common, normal, hard, difficult, dangerous, unusual,impossible, pleasant 等。
如：It is important for her to come to the party.
3。It takes sb. … to do sth.常译为“做……要花费某人……”。
eg: It took thousands of people many years to build the Great Wall.
II. it替代作主语的动词-ing形式的常见句型为：
It is no use / good + doing sth. It”s (well) worth doing sth.。
如：It’s no use talking to him about it.
III. it替代作主语的从句的常见句型为：
A.It is + 名词+ 从句。
It is no wonder / a pity / a shame / one’s duty ..+ that ... (难怪/真可惜/真可耻……)。
如：It is no wonder that she was so angry.
It’s our duty that we protect the environment.
B. It is + 形容词+ 从句。形容词有：important ，necessary, right, strange, …
如：It is natural that he （should）say so.
C. It is + 过去分词+ that ...，能用于这个句型的动词有say, report, think, believe,
hope, expect等. 即: It is said/reported/thought/believed/suggestd + that从句
如：It is reported that the road was closed.
It is believed that he will be in charge of the company.
D. It is suggested ( ordered, required ... ) that ...
该句型和上一个同属一个句型。主句中的过去分词是表示请求，建议，命令等词时，that 后的从句要用虚拟语气（should + 动词原形），should 可以省。
It is suggested that the meeting ( should ) be put off.
It was ordered that we ( should ) arrive there in two hours.
E. It is the first ( seco nd … ) time that …(现在完成)
It was the first ( second … ) time that …(过去完成时)
Eg: a. It（This）is the first time that I have been here.
b. It (That) was the second time that she had visited the temple.
F. It happens/ seems/ appears.. that...该句型中it是形式主语，that 引导的是主语从句，
eg: It happened ( so happened ) that he met his teacher in the street.
It seems/appears that he will be back in a few days.
G. It matters/ doesn't matter whether...
该句型中whether 引导的从句是真正主语，该句型常译为“不论（是否）…没关系……。
eg: It doesn't matter whether they are old (or not).
该句型中的it 作形式宾语。为了记忆方便我们可称该句型为：【6123结构】
6 指主句中常用的动词：think, believe, make, find, consider, feel ； 1 指的是形式宾
语it ； 2 指的是宾补的两种形式：形容词或名词；3 指的是真正宾语的三种形式：不定式短语，动名词短语或that 引导的宾语从句。
We think it our duty to clean our classroom every day.
He felt it important to learn English well.
They found it difficult that they would finish their work in two days.
I found it possible to do this regularly.
She thought it no good worrying about him.
We all thinks it no use standing here to wait for me.
He has got to make it clear that his family is very poor.
