一、考点聚焦
1、it的基本用法
（1）用作人称代词，代替前文提到过的事物。
The train has arrived. It arrived half an hour ago.
（2）用以代替提示代词this, that。
-What’s this? -It’s a knife.
-Whose watch is that? -It’s mine.
（3）起指示代词的作用，指一个人或事物。
-Who is knocking at the door? -It’s me.
（4）指环境情况等。
It was very noisy (quiet) at the very moment.
（5）指时间、季节等。
-What time is it? -It’s eight o’clock.
It often rains in summer here.
（6）指距离。
It is a long way to the school.
（7）作形式主语。
It is not easy to finish the work in two days.
It is no use crying over spilt milk.
It is as pity that you didn’t read the book.
（8）作形式宾语。
I think it no use arguing with him.
I found it very interesting to study English.
He made it clear that he was not interested in that subject.
（9）用于强调结构。
It was Xiaoming whom(that)I met in the street last night.
It was in the street that I met Xiaoming last night.
It ws last night that I met Xiaoming in the street.
It was I who met Xiaoming in the street last night.
2、含有“It is …”的句型
（1）It is time (for sb.) to do sth.
It is (high) time that sb. did sth.(虚拟语气)
（2）It is + 形容词（+of / for sb.）+ to do sth.
通常用 of的词有brave、clever、careful、hopeless、kind、good、naughty、nice、silly、stupid、foolish、wise等。
（3）It is + 形容词 + that + sb. + (should) do sth.（虚拟语气）
能用于这个句型的形容词有strange、wonderful、natural、good、proper、right、wrong、well、fortunate、important、necessary、useless、likely、probable、impossible等。有时可省去should而直接用动词原形。如：
It is important that we should pay close attention to grain.
It is natural that he（should）say so.
（4）It is no use/ good + doing sth.
It is no use trying again = It is of no use to try again.
（5）It is + 被强调部分 + that/who + …
Was it in the street that you met her?
Who was it that called him“comrade”?
It was not until yesterday that I met my old friend.
It is in a small factory that my brother is going to work.（注意上述各句均为强调句型的“考点”）
比较：It is a small factory where my brother is going to work.（定语从句）
（6）It is said/reported/announced/ (well) known … that…
（7）It is/was + 时间 + since … 从……已多久了。
It is three years since I met him in Beijing.
It was a long time since I (had) lived in that small mountain village with these farmers.（注意两句中的时态）
It is five months since I arrived in New York.我到纽约已经五个月了。
It is five months since I was in New York.我离开纽约已经五个月了。
（注意：终止性动词表示从动作发生时算起；如果是状态动词或持续性动词，则从动作或状态结束时算起。）
（8）It is + 时间 + before …
这个句型和上面句型中时间都是时间段，如long、years、months、weeks、five days、three hours、twenty minutes等。不过主句的时态多用一般将来时或一般过去时。
It will be several years before we meet again.
我们要过好几年才能再见面。
It was not long before they set out for the front.
不久他们就出发去了前线。
（9）It is /was/will be the first/second/third … time that …
It is the first time that I have been here.
It was the second time that he had seen the film.
（10）It is up to sb. to do sth … 应由某人做某事。
It is up to you to decide whether we start or not.
二、精典名题导解
选择填空
1. _________ is a fact that English is being accepted as an international language.(NMET 1995)
A.There B.This C.That D.It
解析：答案为D。本题考查作形式主语的用法。that引导的从句是真正的主语。为避免头重脚轻而平衡句子结构，将it置于句首作形式主语。
2. I hope there are enough glasse for each guest to have ________.(NMET 1995)
A.it B.those C.them D.one
解析：答案为D。本题考查替代词it和one的区别。it用于替代同类的、特定的、同一的事物；one替代同类的、泛指的人或物。根据题意“我希望有足够的杯子使每个客人有一个。”可知应用one泛指enough glasses中的一个。
3. Was __________ that I saw last night at the concert?
A.it you B.not you C.you D.that yourself
解析：答案为A。本题考查强调句型的疑问式。只须将句序变为陈述句便不难得出答案。
三、常见用法有以下几类：
1、it可用于代替上文中提到的那一个事物。
2、it可用于代替上文中说到的一件事。
3、it可用于代替不知情的人（尤其是不知身份、性别和姓名的人）。
4、it可用于表示时间、天气、距离、计算结果等。
5、it可用于代替不定式、动名词、从句等，充当形式主语。其常用句型为： It---be---adj./ n. / v-ed---to+V/ V-ing/ Clause
6、it 可用于代替不定式、动名词、从句，充当形式宾语，把真正宾语（不定式、动名词、名词或从句）置于句末。其常用句型为： S---Vt---it---adj./ n.---to+V / V-ing /n./ Clause
7、 it可用于构成强调句，把一个句子中除谓语以外的句子成分（如主语、宾语、表语、状语等）提到句首加以强调。其构成形式是：It is(was) + 被强调成分（不能改变被强调成分的数和格）+ that/ who+原句剩余部分
8、it常用于一些固定结构中，作无人称代词用，充当主语等。
it用法专题练习1：
1---What’s this? ---_______ a map of China
A.This is B.That’s C.It’s D.There’s
2---Where is my pen? ---_____on the desk.
A.This is B.That’s C.It’s D.There’s
3I was disappointed with the film. I had expected_____to be much better.
A.it B.this C.them D.one
4They often help us with our research. ______kind of them.
A.They are B.You are C.It is D.This is
5Tom’s mother kept telling him to work harder, but______didn’t help.
A.he B.she C.this D.it
6John passed the exam successfully and _____was more than we had expected.
A.he B.it C.this D.there
7---Who’s knocking at the door? ---_____ me.
A.It’s B.I’m C.That’s D.This is
8---Who’s the baby in the photo? ---_____ my brother.
A. This is B.That’s C.It’s D.There’s
9_____ Sunday today. Let’s go for an outing.
A.There is B.It’s C.This is D.That’s
10_____ was raining heavily when the film was over.
A.Weather B.Sky C.It D.There
11______a long way from my home to the school.
A.It is B.This is C.There is D.There has been
12---What’s ten added to six? ---______ sixteen.
A.There is B.It is C.This is D.We have
13_____ important to learn English well.
A.This is B.That’s C.It’s D.There’s
14_______ great fun to play basketball after school.
A.It has B.It is C.This is D.Ther