(完整版)高中语法：it用法

It 的用法
It 可用作实词（代词）和虚词（助词）。

实词it 指用于人称和前指（指刚提到的人或物），用于无人称时，做主语，表示时间，距离，天气等。

虚词it 可用作形式主语或形式宾语，也用于构成的强调句型。

（一）实词（代词）
1. 用作人称代词
1）指人。

例如：
Who is it? Is it you, Andrew ?
Who is making such a noise ? It must be the children.
2）用作前指，代替前文提到过的人或事物。

例如：
What a beautiful baby ! Is it a boy ?
You have saved my life; I shall never forget it.
3 ）代替指示代词this, that。

例如：
“What's this ?” “It'sa flag.”
4 ）代替一个双方既知所指的东西
How 'sit going with you ?
2. 用作非人称代词常用作没有具体意义的主语，表示气候，天气，温度，时间，地点，距离等。

例如：1）指天气：
It 'sdamp and cold. I think it 's going to rain.
2）指时间，季节等：
“ what time is it ? ” “It is eight o 'clock. ”
I hope it is spring all the year round.
3）指距离
It is five kilometers from the office to my home.
4）指环境，条件等
It was very quiet and peaceful here,
It was becoming increasing dangerous.
5）“无人称it ”也用于表达下列2 个结构表达印象和可能性：
It seems as if we've known each other for years, （印象）
It looks as though I 'm going to fail the test
6）“无人称it ”还用于下列的表达中
as it is事实上So be it但愿如此，好吧That' s it !对，是这样！make it到达，成功（二）虚词（助词）
1. 作形式主语当动词不定式，动名词，或从句做主语时，通常把她们放在谓语后，而用it 做形式主语。

例：
It is not a good habit to stay up late. （it 表达不定式）
It is no use crying over split milk. （it 代表动名词）
It'sa waste of time your taking to him （it 表示动名词，动名词前可跟一个动名词）
It'sa pity that you didn 'tread the book （it 代表that从句）
2. 作形式宾语
1）当复合宾语中的宾语是不定式，动名词或宾语从句时，往往把宾语放在它的补足语后面，
而用it 作形式宾语。

主语+believe/ consider/count/feel/find/imagine/ think/ make/suppose/take +it+ 宾语补足语（形容词
/名词/介词短语）+ 不定式/动名词/that +从句
You must find it exciting working here. （it 代表动名词）
I made it my business to settle this problem. （it 代表不定式）
2）在下列动词后，用it 充当形式宾语，后接从句。

主语+would appreciate/can make + it+ if 从句
（表示礼貌的请求或建议）
I would appreciate it if you could come to my birthday party.
You can make it if you hurry.
㈢主语+like/dislike/love/hate + it+ when/that+ 从句
（表示喜欢或不喜欢）
I hate it when people stare at me.
③主语+have （声称）；take,count （认为）;hide ; publish , put （表达）+it+that+ 从句Legend
has it that there is a dragon in the lake.
I take it that you will be leaving Shanghai soon.
We published it that we had finished the project ahead of time.
GD 主语+count on （期待）,see to （确保），depend on （依靠）,insist on （坚持），rely on（指望）+it +that+从句
I am counting on it that you will come.
She'll see to it that he goes ahead.
You may rely on it that everything will be ready by Monday.
3）下列动词后，可用“ it+as+名词或形容词”，再接从句。

主语+accept/regard/see/take/view+it+as+ 名词/形容词+从句
I viewed it as a joke when you said you would quit teaching.
I take it as encouraging when students attend all my lecture.
用于强调句型，强调主语，宾语或者状语
It+be+ 被强调部分+that + 句子的其余部分
1）强调主语
It is Prof. Lin who teaches us English.
It was I that/who met Prof, Lin in the street yesterday.
It is the times that produce their heroes.
2）强调宾语
It is English that Prof. Lin teaches us.
3）强调状语
It was in Shanghai that I saw the film.
It was in 1975 that I worked in a factory.
It was yesterday that/when he bought an English book in town.
It was because it raised so many difficult questions that the book took a long time to come out.
4 用于强调特殊疑问句
特殊疑问词+is（was）+it+that+ 句子
Where was it that you met him?
What is it that he wants to see?
练习;
1.He felt ___duty to work for human rights and progress.
A.it his
B. his
C. that is a
D. It is his
2.People in west make___a rule to buy Christmas presents for their relatives and friends.
A.that
B. It
C. This
D. As
3. _no small wonder that that they had so much trouble.
A.this is B That is C there is D it is
4. How long ___ t o finish the work.
A. You 'll take B will take you C you will take it D. Will it take you
5. ___ she first heard of the man referred to as a specialist.
A.That was from Stephen
B. It was Stephen
C. It was from Stephen that
D. It was Stephen that
6. It was playing computer game ___cost the boy plenty of time ___he ought to have spent doing his lessons.
A.that ,that B which, that C which when D that when
7. Was it in 1998 _ he was still at middle school _____ this boy become expert at computer.
A. That where B when where C in which ; in which D, when ;that。