Ｉｔ作主语的用法

李国勤

一、代词it的用法：

A. 用于指代this, that或前面提到或对话双方心目中的人或事物。如：

1. ——Whats this in English?

——Its a pen.

2. The general manager will inspect our workroom this afternoon. Have you heard about it?

B. 在性别、身份不详时指人或指婴儿。如：

——Someone is knocking at the door. Who can it be?

——Its me.

C. 表示时间、距离、温度、环境、天气等自然现象。如：

Its early midnight now. Wed better go to bed. （表时间）

Its about a quarters ride from here to the train station. （表距离）

Its quite warm for January, isnt it? （表天气）

二、引导词it作形式主语的用法：

it 作形式主语，代替由动词不定式短语、动词-ing形式短语或名词性从句所表示的真正的主语，常用结构有：

★ Its+adj./n.+for/of sb. to do sth.

★ Its+adj./n.+doing sth.

★ Its+adj./n.+clause

★ Its+p.p.+clause

如：

(1) Its necessary for us to help each other.

(2) Its not wise of him not to accept his assistants advice.

(3) Its no use arguing with him about it.

(4) Its no wonder that he has passed all the examinations.

(5) Its been suggested that the sports meeting be put off because of the bad weather.

1. it作形式主语，替代作主语的动词不定式，其句型为:

（1）It be adj.（for sb.） to do sth.

此处adj.通常为描述事件的形容词：easy， difficult， hard， necessary，unnecessary， possible， impossible， likely， unlikely， right， wrong，important， unimportant， legal， illegal， well-mannered， ill-mannered， polite， impolite， clear， obvious， certain， suitable， proper， fit， useful，useless， dangerous… 例如:

It is illegal （for a teenager） to drive a car without a license.

（2）It be adj. of sb. to do sth.

此处adj.通常为描述人的形容词：kind， unkind， nice， rude， cruel，considerate， thoughtful， thoughtless， careful， careless， silly， foolish，stupid， clever， wise， crazy等。例如:

Its kind of you to help me with the problem.

2. it作形式主语，替代作主语的动名词的常见句型:

Its no good/use doing…

Its （well） worth doing…

Its （well） worth ones while doing/to do…

Its （well） worth while doing/to do…

例如: Its no use crying over spilt milk.

3. it作形式主语，替代作主语的从句常见句型:

（1）It is +n.+从句 例如:

It is no secret that the president wants to have a second term at office.

（2）It is adj.+clause

Its surprising that…（should）… ……竟然……

Its a pity/shame that…（should）… ……竟然……

例如: Its important that you should apologize to her for your rudeness.（=Its of much importance that you should apologize to her for your rudeness.）

（3）It v. sb.+clause=It is v-ing+clause

It+surprise/delight/interest/disappoint/worry／disturb／annoy／amaze／bother／concern／frighten／please／anger sb. that… 例如:

It worried me that she drove so fast.（=It was worrying that she drove so fast.）

（4）It v. （to sb.） that…=sb./sth. v. to do

（v.=appear， seem， come about， emerge， follow， chance， happen，occur， transpire， turn out， work out）例如:

It（so） happened/chanced that they were out.（=They happened/chanced to be out.）

（5）It is v-ed that…=sb./sth. is to do

（v.=say， report， think， believe， hope， expect， agree， accept， decide， determine， intend， plan， understand， know）例如:

It is said that the couple have gotten divorced.（=The couple are said to have gotten divorced.）

（6）It is v-ed that…（should）…

（v.=demand， request， require， order， suggest， advise， recommend)例如:

It is suggested that they should begin with the third question.

4. it作主语的句型例析

(1) It takes sb.…to do…（=sb. takes…to do…）某人用多长时间做某事 例如:

It took the men a week to mend our roof.（=The men took a week to mend our roof.）

(2) Its （just） （un）like sb. to do…（不）像某人做某事的风格 例如:

It was （just） like him to think of helping us.

(3) Its（about/high） time that…should/v-ed…是该做某事的时候了 例如:

Its （about/high） time that we should take action.

(4) Its the x-th time（that）…have v-ed…第几次做某事了 例如:

Its the third time that he has failed the driving test.

(5) It is/has been…since…continuous v-ed（延续性动词）某动作已有多长时间不发生了 例如:

Its 10 years that he lived here.

(6) It was （not）…before…过（不）了多长时间某动作发生了 例如:

It was not long before they arrived.

巩固练习：

从A、B、C、D四个选项中选出可以填入空白处的最佳选项。

1. ——____ that you are doing these days?

——Nothing.Im just playing some computer games at home.

A. What is it B. What it is C. What is D. What are

2. ——____ that you came here yesterday?

——By train.

A. How is itB. How was it C. How it isD. How it was

3. ——Steven has got the first prize in the math contest.

——____ is no wonder that he looks so happy.

A. It B. As C. There D. That

4. ____ being Sunday, the library is closed.

A. That B. It is C. It D. This

5. ____ is reported that he got seven gold medals.

A. That B. As C. It D. This

6. ____ that you didn't know the river Thames.

A. It's a pity B. What's a pity

C. That's a pity D. There's a pity

Key:1.A 2.B 3.A 4.C 5.C 6.A