⑵.作指示代词(demonstrative pronoun) 可用来代替this ,that.

⑶.作非人称代词(impersonal pronoun )，表示时间、天气、季节、距离、环境等。

Step 2. Presentation and summary

⑴．It 作形式主语:为了避免句子头重脚轻，英语里面常常把it放在句子的开头，而把真正作为主语的动名词、不定式和句子放在整句的的后面。 "it"并无实际意义。

Then ask students to conclude the sentence structure of "it" in

groups.Show the sentence structure of it as formal subject on

the screen.

e.g It's no use crying over spilt milk.

It is different to give up smoking .

It was disappointing that he refused my invitation.

⑵．It 作形式宾语：it做形式宾语；不定式短语、动名词短语或that 从 句做真正宾语，放在宾语补足语之后。形容词或名词做宾补；

主句中常用的动词：think,believe,make,find,consider,feel；

①. He feels it his duty to help others.

②. He made it clear that he didn't want to talk about it.

③. He felt it no use learning English without speaking it.

⑶.强调句：It is（was） + 被强调部分 + that ...

使用该句型有以下几点请注意：

① 强调句的谓语is或was永远用单数.