It的用法?What从句用法?

It的用法?What从句用法?
It的用法?What从句用法?

It的用法?What从句用法?
IT 的用法
1.做代词,代替刚提到的过的一件事情.
a. 可以指一个具体的东西.b. 可以指前面所谈的事情或情况.
eg. a. It’s a nice room.
b.You promised to write the article, and you must do it.
2.做代词代替指示代词 this, that
eg. ---What’s this? ------ It’s a flag.
3.起指示代词的作用,指一个人或事物,it 所指的东西不很具体.
a.有时指某个动作的人.b .有时指引起某种情况的事物.
eg. a.. ----Who is knocking at the door? ---- It’s me.
b.It’s the wind shaking the window.
4.指环境,情况等.
eg. It’s very quiet at the moment.
5.指自然现象（天气,气候,明暗等）
eg. I’s getting cold (dark, late, etc.).
6.指季节,时间
eg. It was late autume (early spring, mid summer, etc).
7.指距离
eg.It’s only five miles (half an hour’s walk).
8.用于强调结构,在这里it 可以说没有意思.它只帮助改变一个句子的结构,使某一成分受到强调,改变结构的办法是：
IT + be + 要强调的部分+ that(who, whom) + 句子其他部分
强调的部分是人用who(m), 其他情况多用that
eg. It was Mary who (that) met your sister in the zoo yesterday.
It was your sister that (whom) Mary met in the zoo yesterday.
It was in the zoo that (where) Mary met your sister yesterday.
9.做形式主语,代替一个由不定式,动名词短语或是从句表示的主语,使原来的这些主语可以放在句子后部,避免头重脚轻.
a. 真正的主语是不定式.
Eg.It’s our duty to attend to this letter.
b.真正的主语是动名词.
Eg.It’s no use talking to him about it.
c.真正的主语是从句, 这个从句可以用that 引起,也可以用一个连接代词或连接副词引起.
Eg.It happened that I wasn’t there that day.
It’s doubtful whether she will be able to come..
10.做形式宾语,代替一个由不定式,动名词,或是宾语从句,往往把宾语放在它的补足语后面.而用it做形式宾语,放在宾语补足语之前.
Eg.I think it no use arguing with him.
二：what引导主语从句.以下有举例：）~
例】After Yang Liwei succeeded in circling the earth, _____ our astronauts desire to do is walk in space.
A.where B. what C. that D. how [04上海卷]
【题意】杨利伟成功地环绕地球飞行之后,我宇航员所渴望做的事情是在太空行走.
【考点】what引导主语从句.
【简析 【简析】通过分析题干结构可以看出,主句主语是由一个句子充当的,而且这个句子中的谓语desire缺少宾语,应该排除A、D两项；在引导主语从句时that无词义,因此正确答案是：B.
2．【考例】I think Father would like to know _____ I’ve been up to so far, so I decided to send him a quick note.
A.which B. why C. what D. how [04湖南卷]
【题意】我认为父亲想知道目前我在做什么,所以我决定给他发个短信.
【考点】what引导宾语从句.
【简析 【简析】know后面跟有一个宾语从句,从句中be up to缺少宾语,所以应该选一个连接代词引导宾语从句,这样B、D是错误的；A项不符合题意,正确答案是：C.
3．【考例】---Are you still thinking about yesterday’s game?
---Oh, that’s _____ .
A.what makes me feel excited B. whatever I feel excited about
C. how I feel about it D. when I feel excited [03北京春季]
【题意】---你还在想昨天的比赛吗? ---哦,那就是使我感到兴奋的事情.
【考点】What引导表语从句.
【简析 【简析】根据问话人的意图,想知道的不是“怎么样”、也不是“什么时候”；所以排除C、D两项；B项不合题意.答案是：A.
4．【考例】Our hometown has changed a lot, and now it is quite different from _____ a few years ago.
A.what it used to be B. that it used to be C. which it used to be D. what was it
【题意】我们的家乡变化很大,它现在与数年前的样子完全不同.
【考点】what引导宾语从句.
【简析 【简析】介词from后面是一个宾语从句,分析所给的选项可以看出,be应该带有 自己的表语意思才能完整,这样B、D两项错误,C项不符合题意.正确答案是：A.
5．【考例】A modern city has been set up in _____ was a wasteland ten years ago.
A.what B. which C. that D. where [04天津卷]
【题意】一座现代化城市已经在十年前是垃圾场的地方拨地而起.
【考点】what引导宾语从句.
【简析 【简析】介词in后面应该是一个名词性的结构,再加上这个结构中缺少的是主语,而不是地点状语,因此要首先排除D项；B、C两项不合乎题意.答案是：A.
6．【考例】It is pretty well understood _____ controls the flow of carbon dioxide in and out the atmosphere today.
A.that B. when C. what D. how [03上海卷]
【题意】今天人们十分明白是什么控制着大气层内外二氧化碳的流动的.
【考点】what引导主语从句.
【简析 【简析】it在整个题干中做形式主语,understood之后的部分是真正主语,是主语从句,根据题意可以排除B、D两项；要使主语从句的意义和结构完整,正确答案应该是：C.
更详细的可以看语法大全：）~
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