Unit 2 language grammar学案

一、双基提要

It的用法

1人称用法

人称用法是指it可以用来代替一个名词、一个短语、一个从句或一个句子，以避免它们在句中的重复。这时它可以指提到过的，也可以指未提到过的，在句中作主语或宾语。

（1）指非生物、动植物和不明性别的婴儿。That is a new magazine. I bought it this morning.

（2）指成员众多的集体

The acrobats performed for a large audience last night. It was very excited by the show.

（3）指某一动作或事情 I like dancing,but she doesn't like it.

2指示用法

　　指示用法是指it用在句型"It is/was+表语"中，指明某人或某物的身份。这时它可以代替this或that，作用同this或that，指提到过的或未提到过的。

What's that? It's a computer.

3先行用法

（1）指代不定式。How long does it take to travel from Beijing to Shanghai.

（2）指代动词-ing形式。以 It's no use, It's no good等开头的句子常以-ing分词作真正主语。

It's no good crying over spilt milk. It's no use trying to persuade him.

（3）指代名词性从句。 It is pity that you didn't see such a good film.

4无人称用法

（1）用于表示自然现象、时间、距离、环境等。 Is it cold in this room? No, it isn't.

（2）用于以连系动词seem, appear, look, happen等作谓语，后接一个that从句的句中。

It seems that he is always correct. It appears that she is an experienced teacher.

5强调用法 强调it本身无词义。它用来强调句中放在表语位置的某个句子成分（谓语动词除外），其强调句型为："It+is/was+被强调成 分（通常为主语、宾语、状语）+从句（由 that/who 引导）"。

名词性从句考点及热点问题

名词性从句包括主语从句、宾语从句、表语从句和同位语从句。因为它是从句，因此具有句子的特点，有主、谓成份；同时又具有名词性特点，所以可以在句子中作主语、宾语