英语it用法归纳及练习50题：doc全文下载 href="/Upload/UploadFiles//coach_UploadFiles_8112/201311/2013112710014859.doc">高中英语it用法归纳及练习50题：doc全文下载
一、虚词it 虚义it指用作没有具体语义的主语，如表示时间、天气、距离、温度、环境等概念的用法。
It is cooler in
It is only about half an hour's ride from here to my home.
It’s three o’clock now.
It looks as if the college is very small.
It is very guiet at the moment.
二、指代
it的基本用法是用来指代上文所提到的事物,同时也可以用以代替指示代词this,that.
1.My dictionary is missing, I can’t find it anyway.
2.Tom has failed in the exam, have you heard about
it?
3.– What’s this?
-- it’s a computer.
4.– Whose bicycle is that?
-- it’s hers.
it, one, 用于指代用法时的区别:
it代替上文提及的原物(复数用they)；one指代上文提及的、泛指的可数名词单数（复数ones）
Do you want the watch?
Yes, I want it.
Do you want a watch?
Yes, I want one.
What is a panda like?
I’ ve never seen one, so I dont’ know what it is like.
指代不明身份或性别的人也用it ,有时可以用来指婴儿，有时还可以指引起某种情况的事物。
1.A:---Who is making such a noise?
B:---It must be the children.
2.It’s the wind shaking the window .
3.Look that lovely baby in the cradle! Oh, dear. It is crying.
4.A：Who's it (knocking at the door)?
B: It's me.
三、形式it:
1．形式主语：不定式、动名词以及主语从句作主语时，为避免“头重脚轻”，要将真正的主语后置。
It seemed impossible (for him) to get back home.
It was worthwhile searching for his "roots."
It was obvious that his ancestor taught his younger generation little of his own language.
1. It is clear ( obvious, true, possible, certain…) that …
该句型中it 是形式主语，真正的主语是 that 引导的主语从句，常译为 “ 清楚（显然，真的，肯定……）”是主语从句最常见的一种结构。
It is very clear that he's round and tall like a tree.
= That he's round and tall like a tree is very clear.
2. It is important ( necessary, right, strange, natural...) that ...
该句型和上一个同属一个句型。由于主句中的形容词不同，that 后的从句中要用虚拟语气（should + 动词原形），should 可以省去。建议记住该句型中的形容词。
It is important that we (should) learn English well.
It is necessary that he (should) remember these words.
3. It is said (reported, learned…) that …
该句型中的it 仍是形式主语，真正主语是 that 引导的主语从句。该结构常译为“ 据说（据报道，据悉……）”。
It is said that he has come to Beijing.
It is reported that another man-made satellite has been put into orbit
4. It is suggested ( ordered, required ... ) that ...
该句型和上一个同属一个句型。主句中的过去分词是表示请求，建议，命令等词时，that 后的从句要用虚拟语气（should + 动词原形），should 可以省。常译为“ 据建议；有命令……）”。
It is suggested that the meeting ( should ) be put off.
It was ordered that we ( should ) arrive there in two hours.
5. It is a pity ( a shame ... ) that ...
该句型中，that 后的从句一般用虚拟语气（should + 动词原形），should 可省去．表示出乎意料，常译为“竟然”。没有这种意义时，则不用虚拟语气。
It is a pity that such a thing ( should ) happen in your class.
这种事竟然发生在你们班上，真是遗憾！
It is a pity that he is ill. 他生病了，真遗憾！
6. It is time ( about time , high time ) that ...
该句型中that 后的从句应该用虚拟语气，值得注意的是：① 常用过去时态表示虚拟．② 有时也用should + 动词原形，should 不能省。常译为“是（正是）……的时侯……”。
It is time that children should go to bed.
= It is time that children went to bed.
7. It is the first ( second … ) time that …
该句型要和上一个句型区别开来。该句型中的 that 从句不用虚拟语气，而用完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。该结构中 that 可以省去；it 有时用 this 替换，常译为“是第一（二）……次……”。
It is the first time I have been here.
= This is the first time I have been here.
8. It is … since ...
该句型主要用作处理瞬间动词的完成时，又要和表示一段时间的时间状语连用的问题。主句中是时间作表语，其时态是现在时或完成时，since 引导的从句通常是一般过去时态，而且是瞬间动词。如果主句是一般过去时，从句则用过去完成时。
It is ( has been ) 5 years since his father died.
9. It is ... when ...该句型中的 when 引导的是一个时间状语从句，主句中的 it 指时间，表语由具体的时间充当。常译为“当……的时候，是……”。
It was 5 o'clock when he came here.
