Module 2 Environmental problems Unit 4 Natural disasters语法--it的用法归

牛津深圳版九年级英语下册 Module 2 Environmental problems
Unit 4 Natural disasters 语法
it用法完全归纳

一、it 作人称代词的用法
1. 指事物
作为人称代词，it 可以除人以外的一切事物或动物。如：
I dropped my watch and it broke. 我把手表掉在地上摔坏了。
“Where is the dog ” “It’s in the bedroom. ” “狗在哪 ”“在卧室里”。
2. 指人
it 指人主要用于指不性别不明的婴儿或用于确认某人的身份。如：
Is it a boy or a girl 是男孩还是女孩
There is a knock on the door. It must be the postman. 有人在敲门，一定是邮递员。
－Who is the baby －It‘s my teacher’s son．
【说明】在答语中，常用来指本人，如说 It’s me。
3. 代替某些代词
代词 it 还可用于代替指示代词this, that 以及复合不定代词 something, anything, nothing等。如：
“What’s this ” “It’s a new machine. ” “这是什么 ”“是一种新机器”。
Nothing is wrong, is it 没出什么问题，是吗
It/that/one 的区别
--- There is still a copy of the book in the library. Will you go and borrow it （指代a copy of the book）
--- No, I’d rather buy one in the bookstore.(2007陕西卷)
二、it 作非人称代词的用法
1. 基本用法
it 作非人称代词的用法，主要用于指时间、距离、价值、天气、气候及温度等自然现象。如：
It’s too late to go there now. 现在去那儿已经太迟了。
It rained all day yesterday. 昨天下了一天的雨。
It can get very hot here. 这里有时会很热。
It’s ten past six. (指时间)
It’s warm at the moment. (指天气)
It’s two miles to the beach. (指距离)
2. 用于某些句型
It’s time for sth. 该做某事了。
It’s time to do sth. 该做某事的时候了。
It’s time for sb to do sth. 某人该干某事了。
It’s (about / high) time + that-从句. 某人该做某事了。(从句谓语用过去式，有时也用“should+动词原形”)
It’s first (second) time + that-从句. 某人第几次干某事。(从句谓语用现在完成时)
It’s + 时间段 + since-从句. 自从……有一段时间了。
It’s + 时间段 + before-从句. 过多长的时间才……
三、it用作形式主语
1. 基本用法
用作形式主语.it 没有具体意义，而只是帮助把真正的主语移至句子后尾，使句子显得平稳一些，能借it 给移至句子后尾的主语有三种：一种由不定式表示，一种由动名词表示，一种由从句表示。
1).It 替代真正的主语——动词不定式短语.
It is easier to say than to do .
It is a good act to help the others.
2).it 替代真正的主语——动名词短语,以动名词短语做主语的句子，主要在以no good, no use, worth
,a waste of time,it is fun等词作表语的句中.
3).it 替代从句作主语，用从句做主语的带it 的句子很多,常见的有下面几类：
① It is a pity (a shame ,a fact ,a wonder ,a good thing, etc. ) that…
It is a shame that he didn’t pass the exam.
② It is strange ( surprising, obvious ,true, good, possible, clear, etc. ) that… 。
It was clear that they had no desire for peace.
③ It seems (happened ,turned out, etc.)that…
It seemed that things were not as they expected.
④ It is said ( decided ,expected ,etc)that …
It is said that the tickets have been sold out .
2. 用作形式主语的的重要句型
(1) It + be + adj. for (of) sb to do sth 某人做某事……
It is hard for him to make up his mind. 他很难下定决心。
It was foolish of her to say such a thing. 她说那样的话，真是太蠢了。
【说明】介词 of 与 for 的区别是：of 用于指某人的性格、属性、特征等，介词for表示对象，意为“对……来说”
(2) It takes sb + 时间段 + to do sth. 某人做某事花了……时间
It takes years to master a new language. 要花多年的时间才能掌握一门新的语言。
【说明】此句型可以有以下多变种变体：It took me an hour to write the letter. =The letter took me an hour (to write). =I took an hour to write the letter. 我写这封信花了一个小时。
(3) It is up to sb to do sth. 该由某人做某事
It’s up to you to to make the choice. 得由你来作选择。
(4) it look (seem, appear, happen, occur) that [as if]… 似乎……
It seemed as though he didn’t recognize me. 他似乎没认出我来。
It happened that I was out when he called. 他打电话时我碰巧不在家。
四、it用作形式宾语
1. 基本用法
当不定式、动名词、从句等复杂成分用作宾语且其后跟有宾语补足语时，通常会在宾语补足语前使用形式宾语，而将真正的宾语移至句末。其基本结构为“动词+it+宾语补足语+不定式(动名词或从句)”。如：
I find it difficult to do the job well. 我发现做好这件事不容易。
I think it best that you should stay here. 我认为你最好住这儿。
We think it no use complaining. 我们认为抱怨是没有用的。
It 的用法练习
【实战演练】
一．单项选择。
1.Is ____ necessary to take off our shoes when we enter the lab
A. everyone B.this C.her D.it
2. Is ____ possible to fly to the moon in a spaceship
A.now B.that C.it D.man
3. I don’t think ___ possible to master a foreign language without much memory work.
A.this B.that C.its D.it
4.She heard of a terrible noise, ___ brought her heart into her mouth.
A.it B.which C.this D.that
5.Alice received an invitation from her boss, ____ came as a surprise.
A.it B.that C.which D.he
6.Does ____ matter if he can’t finish the job on time
A.this B.that C.he D.it
7.Tom’s mother kept telling him that he should work harder, but ____ didn’t help.
A.he B.which C.she D.it
8.The weather turned out to be very good, ___ was more than we could expect.
A.what B.which C.that D.it
9.____is a fact that English is being accepted as an international language.
A.There B.This C.That D.It
10.I hope there are enough glasses for each guest to have _____.
A.it B.those C.them D.one
11.I hate ____ when people talk with their mouths full.
A.it B.that C.these D.them
二， 根据句意, 判断句子中划线的it指代的是什么。
1. It is 30℃. You can take off your coat.
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2. It is ten kilometers from my home to your home.
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3. It is almost eleven o’clock. You should go to bed.
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4. It is winter in China. How about in Australia
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5. It is sunny. Let’s go out to take a walk in the park.
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II. 写出句子中划线的it指代的是哪一部分。
6. It is impossible for you to get to the top of the Himalayas.
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7. It seems that the poor man doesn’t want to get others’ help.
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8. It is nice to read a book on rainy days.
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9. It appears that the dog is sick.
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10. It is boring to watch the same movie again and again.
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三. 连词成句。
11. afternoon, it, five, is, in, o’clock, the (.)
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12. with, it, nice, is, be, you, to (.)
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13. that, it, appears, friends, no, impolite, wants, to, make, with, the, one, boy (.)
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14. today, it, is, and, you, hot, can, wear, dress, your (.)
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15. it, that, girl, seems, the, better, becomes, now(.)
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