it

it作形式主语和形式宾语的用法
it可作：①代词②形式主语③形式宾语。

一it作形式主语
不定式，动名词，从句作主语时，常用it 作形式主语置于句首，而将真正的主语放在句尾。

此时it 只起先行引导作用，本身无词义。

It is wrong to tell a lie.
it作形式主语的常见句型：
①It is + 形容词(+ for /of sb) + to do sth/doing sth/that…
(clear, certain, important, necessary, obvious)
eg. It is hard for him to make up his mind.
It was foolish of her to say such a thing. 她说那样的话，真是太蠢了。

It is surprising that she married a man like that.
It is natural that… 很自然…
It is strange that… 奇怪的是…
of 与for 的区别：of 用于指某人的性格、属性、特征等，for表示对象，“对……来说”
②It is+名词(词组)+doing/that… (fact, idea, pity, pleasure, shame, news)
eg. It is no good telling lies. It was his duty to do sth.
It is a shame that I failed the exam. It is a pity that you didn’t go to see a film. It’s no good doing sth.
It’s no use doing sth.
It is no/ little wonder that…
It is useless doing sth.
It is a fact that … 事实是…
It is an honor that …非常荣幸
It is common knowledge that …是常识
③It is+过去分词+that…
该句型常见词: said, hoped, thought, suppose, expect, reported, known, believe, consider, decide, It is reported that… 据报道…
It has been proved that… 已证实…
It is said t hat… 据说…
④It seems/ appears似乎…/ happens碰巧… /looks /occurs+ that /as if…
eg. It seemed as if he didn’t recognize me. 他似乎没认出我来。

It seems that he enjoys pop songs very much.
It appears that he might change his mind.
It happened that I was out when you called. 他打电话时我碰巧不在家。

⑤如果句子是疑问形式，就只能用it 作形式主语。

eg. Does it matter much that they won’t come tomorrow? 他们明天不来很重要吗？
Is it true that he will go abroad next week? 他下周出国是真的吗？
⑥if引导主语从句时，只能用it作形式主语，放在句首，而将if主语从句放到句末。

eg. It is uncertain if he will leave for Beijing tomorrow. 明天他是否去北京还不敢肯定。

⑦It takes ( sb.) time to do sth.
⑧It is up to sb. to do sth. 该由某人做某事
eg. It’s up to you to to make the choice. 得由你来作选择。

⑨If it were not for… / If it hadn’t been for… 若不是因为……
eg. If it were not for their help, we couldn’t have got over the difficulties.
（二）it 作形式宾语
当不定式，动名词，或从句在某个句子中作宾语时，常用it 作宾语。

而将真正的宾语放在句尾。

此时it 只起先行引导的作用，本身无词义。

常见句型如下。

①动词+ it + 宾语补足语+ 宾语
make/ find/ feel/ think/ suppose+ it +adj/ n. + to do/ doing/ that…
eg. We thought it a pity that she should have missed the chance.
make it a routine to watch a film once a month
②某些表示喜怒哀乐的动词，如like, enjoy, love, hate等，往往不能接宾语从句。

sb. like/ love/ appreciate/ hate/ dislike it that…
eg. I don’t like it that he is so lazy.
I hate it that my mother asks me to eat eggs.
③that引导的宾语从句不能直接作介词的宾语，sb. depend on it that…
eg. You may depend on it that we shall always help you.
④由及物动词与介词组成的固定搭配中，宾语从句若作该动词的宾语时，须借用it。

如：
We owe it to you that there wasn’t a serious accident.多亏了你才没有发生重大事故。

三. it作代词
1. 代指上文出现过的事、物。

特指。

也可作人称代词，代两种人：“婴儿”，“性别和身份未知的人”
----Who made the bedroom so dirty?
----It was the naughty boys?
2. 代指天气、日期、时间、温度、距离、重量等。

---Do you like it here?
---Oh, yes. The air, the weather, the way of life. Everything is so nice.。