曾　军　张忠良

it是高考测试的热点内容之一，它不仅可以指代时间、地点、天气、距离等，还可以作形式主语和形式宾语，同时还可以用于强调句结构中，下面就结合高考题来谈谈它的用法，希望能对同学们的学习有所帮助。

一、 it用作代词

1.it指代前文提到过的事物，可指前面刚提到的同一事物或某人。如：

I was disappointed with the film. I had expected ____ to be much better. (93NMET)

A. that B. this C. one D. it

[解析]首先让我们看that, one, it这三个代词的用法区别：it用来替代前面提到的同一事物,one作替代词,相当于“a(an)+名词”，用来代替前面出现过的“同类”事物,that用来替代前面提到的特指的事物,本题中的代词是代替上文中提到的the film，应用it，答案为D。

2.指代前一个句子的内容或情况。如：

The doctor advised Vera strongly that she should take a holiday, but ____ didnt help. (05全国卷Ⅲ)

A. it B. she C. which D. he

[解析]因为有连词but，不能用关系代词which，it用来代替上文“The doctor advised Vera strongly that she should take a holiday”这个句子的整体意义，答案为A。

3.it指代天气、时间、距离、地点、温度、自然环境等。如：

(1) ____ from Beijing to London! (93NMET)

A. How long way it is B. What a long way is it

C. How long way is it D. What a long way it is

[解析]it在此指距离，这是一个感叹句，修饰名词用what，答案为D。

(2) ——Did Jack come back early last night? (05福建)

——Yes. It was not yet eight oclock ____ he arrived home.

A. before B. when C. that D. until

[解析]it在这里代指时间，根据题干“他到家时还不到八点”，可知是when（当……时候）引导的时间状语从句，答案为B。

(3) It was some time ____ we realized the truth. (05山东)

A. when B. until C. since D. before

(4) It was not long ____ a customer who had seen him arrive dropped

in to inform him that his car was covered with bees. (05重庆)

A. when B. after C. until D. before

[解析]It is/was/will be+段时间+before从句,这一句型意为“还有……时间就……”，为否定句时，段时间只能是long一词,整个句型表达“不久……就……”,所以答案为(3)D (4)D。

(5) That was really a splendid evening. Its been years ____ I enjoyed myself so much. （05安徽）

A. when B. that C. before D. since

[解析]It+is/has been+一段时间+since从句,意为“自……以来已有多长时间了”或“自不……以来已有多长时间了”。在该句型中若since从句的谓语动词是非延续性动词,则表示从句中的动作延续多长时间了;若since从句的谓语动词是延续性动词或状态动词,则表示从句中的动作已结束多长时间了,答案为D。

二、it 作先行词，在句中充当形式主语或形式宾语，而把真正的主语或宾语如动词不定式、动名词短语、主语从句或宾语从句等移到句子后边去。

1.作形式主语，it作先行词，在句中充当形式主语常用于下列几个句型：

(1)Its+名词/形容词……+不定式。如：

① In fact ____ is a hard job for the police to keep order in an

important football match. (01上海)

A. this B. that C. there D. it

[解析]it作形式主语，代替真正主语to keep order in an important football match不定式短语，答案为D。

② Who is it up ____ ____ the first company ____ is run by the state? (02北京春)

A. to; take charge of; which B. to; to take charge of; that

C. for; to take charge of; that D. to; to taking charge of; which

[解析]该句结构比较复杂，将疑问句还原为陈述句可知是“Its up to sb. to do sth.”句型，该句型意为“该由某人负责做某事”，company后跟定语从句，先行词前有序数词first修饰，关系代词用that，答案为B。

(2)Its+名词+动名词短语。如：

It is no ____ arguing with Bill because he will never change his mind.(06全国)

A. use C. help C. time D. way

[解析]It is no use doing sth.意为“做……没有用”，it为形式主语,而把真正的主语动名词短语arguing with Bill 放在后面，答案为A。

(3)Its+过去分词+名词性从句，常用于该句型的过去分词有: said, told, reported, known, suggested, hoped, expected等。如：

____ in the regulations that you should not tell other people the password of your email account. (05上海)

A. What is required B. What requires

C. It is required D. It requires

[解析]it是形式主语，代替that引导的主语从句，答案为C。

(4)Its+名词/形容词+名词性从句。如：

① He hasnt slept at all for three days. ____ he is tired out.(05湖北)

A. There is no point B. There is no need

C. It is no wonder D. It is no way

[解析]根据语境可知，“他已经三天没合眼了，难怪他精疲力竭了”,It is no wonder+that…该句型意为“难怪……”，可省略成 No wonder+that…，答案为C。

② ____ is our belief that improvements in health care will lead to a stronger, more prosperous economy. （06浙江）

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

[解析]it是形式主语，代替that引导的名词性从句，答案为D。

2.作形式宾语，这种情况通常只用于能带以名词或形容词作宾语补足语的动词后面。如：

(1) The chairman thought ____ necessary to invite Professor Smith to

speak at the meeting. (05全国卷Ⅲ)

A. that B. it C. this D. him

[解析]think后接复合宾语，不定式短语“to invite Professor Smith to speak at the meeting” it有形容词necessary 修饰作宾语补足语，只能用 it 作形式宾语，而把不定式短语放在后面，答案为B。

(2) As the busiest woman in Norton, she made ____ her duty to look

after all the other peoples affairs in that town. (06湖南)

A. this B. that C. one D. it

[解析]made后接复合宾语，it作形式宾语，代替不定式短语“to look after all the other peoples affairs in that town”,答案为D。

(3) I hate ____ when people talk with their mouth full. (98NMET)

A. it B. that C. these D. them

[解析]it作形式宾语，代替when引导的宾语从句，答案为Ａ。

三、用于强调句型，这种强调句的结构是“It is （was）＋所强调的成分（主语、宾语、状语、从句）＋that…”，表达的意思为“是……，正是……，就是……”，“it”在这种句型中本身没什么实际意义， 如被强调的是人，则后面用who或that， 如被强调的是物或其他情况，则用that。如：

1. David said that it was because of his strong interest in literature ____ he chose the course. （06上海）

A. that B. what C. why D. how

[解析]本句对“because of his strong interest in literature”短语进行强调，用that，答案为A。

2. It was after he got what he had desired ____ he realized it was not so important. （06辽宁）

A. that B. when C. since D. as

[解析]本句对“after he got what he had desired”时间状语从句进行强调，用that，答案为A。