"It" 用法及其句型和固定搭配，是高中英语语法的重点、难点，又是近几年高考的热点，因此应给予充分的重视。

初小内容归纳：

一、it指代（后行）作用:

1.It 的基本用法是用来指代上文所提到的事物。如橙子妈妈经常给学生用最简单的方法举例：

I have a pen and I like it.

2.学会区分这几组词： it, that, one, the one, ones, the ones 用于指代 :

橙子妈妈归纳的口诀：it指代同名同物；one指代同名异物, that指代抽象物体居多

即it代替上文提及的原物(复数用they)；one指代上文提及的、泛指的可数名词单数（复数ones）；that指代上文提及的定指的可数名词单数或不可数名词（复数those）, the ones 相当于these, those。

注意： 指代不明身份（例如有人在外面叫你或者敲门）或性别的人（如小baby）也用 it ；指代喜爱的事物或宠物也可用 she / he 。

A：Who's it (knocking at the door)? B: It's me.

二、虚义 it:（初中阶段的重点内容）

虚义it指用作没有具体语义的主语，如表示时间、天气、距离、温度等概念的用法。

It is a good day.

It cost me 10 dollars.

高中内容归纳

一、 形式 it:

由于句子结构的需要，常常把it作形式主语，而把真正的主语放后置。小伙伴们熟不熟悉！

1 ．形式主语：不定式、动名词以及主语从句作主语时，为避免“头重脚轻”，要将真正的主语后置。

It is obvious that he will win the match. （主语从句作主语）

It was worthwhile searching for his "roots." （动名词作主语）

It took me 10 dollars to buy the book. （不定式作主语）

2 ．形式宾语：当不定式、动名词、that 从句作宾语，又有自己的宾语补语时，要 用it 作形式宾语，而把真正的宾语后置。能够用于形式宾语句型的动词有think, make, find, consider, feel, take等。如：

She found it important to study the situation inRussia.

The fisherman made it a rule that he never cast his net more than four times a day.

The ancient people took it for granted that the earth was flat.

We think it necessary listening to the radio everyday.

二、强调it: 为了强调句子中的某一成分，可以用“It is / was ＋ 被强调部分 ＋that / who＋其它”的句型。如：

She helped me last week.

强调句（强调时间）：It was last week that she helped me.

橙子妈妈要重点介绍的是关于not...until 这一句式结构的强调形式，例如：

My dad didn't come back until 9 o'clock.

It was not until 9 o'clock that my dad came back.（记住一定要将not until放在一起，而且从句中的时态需要变化）

注意：１）一般强调时间不能用when, 强调地点不用where;　２）强调谓语用下列方式（在谓语动词前面用do\ did\does）：　I do hate it.

三、 注意强调句型与定语从句的区别

例 It was at 7 o'clock that he came here yesterday.(强调句型)

It was 7 o'clock when he came hereyesterday.(定语从句)

区别：将 It is/was ··· that(who) …结构去掉，如果句子成立，可判断为强调句。

It 练习巩固

1、_____ seemed that the water was to blame.

2、I find_____ unnecessary to explain the reason to you.

3、What a lovely baby! Is ____ a boy?

4、I’d appreciate _____ if you would like to teach me how to use the computer.

5、We don’t consider______ impossible for them to break into that house.

6、I didn’t realize how much you loved me until last night. (改为含not until的强调句)

________________________________________________________________.

7、The alcoholic did not feel as fit as before until he quit smoking. 强调加粗部分

________________________________________________________________.

8、 I happened to meet her on my way back home. →

It ______ ______ ______ ______ her on my way back home.

9、People suggested that the meeting be put off.

__________ ___________ ___________ ____________ the meeting be put off.

10、Obviously, we don’t want to spend too much money.

___________ _____________ _____________ ____________ we don’t want to spend too much money.

11、According to some scientists, 2011 is likely to be the coolest year since 1956.

According to some scientists, ___________ __________ ___________ __________ 2011 will be the coolest year since 1956.

12、It is likely that John will be in London this autumn.

___________ ___________ ____________ ___________ be in London this autumn.

13、 It is likely that the thieves don’t know how much it is worth.

___________ ___________ ____________ ___________ not to know how much it is worth.