逍遥右脑 2010-04-14 21:26
It 的用法
１．作人称代词
John likes playing Pingpong．/ He always does it in the afternoon．(指代上下文提到的事物)；/ It's time we went home. / How far is it from here to your home ? / It is getting warmer and warmer．/ It's very quiet at the moment．(可指时间、天气、环境等)
２．引导词
Ａ．作形式主语，代替由不定式、动名词或从句表示的真正主语。
It's important for us to learn a second language．/ It's no use talking to him．/ It's known to all that the earth goes round the sun．
B．作形式宾语，代替由不定式、动名词或从句表示的真正宾语。
We feel it our duty to help others．/ He made it clear that he would leave the city．
C．强调结构：It is (was) 被强调部分＋that (或who)…
注意: 在强调结构中，如被强调部分为时间状语或地点状语，其后的连接词也绝不能为when 或where，而应用that 。在复习中，一定要注意句式的不同。
It was in Shanghai that I bought the guitar．(that引起强调句)
It was Shanghai where I bought the guitar．(where引起定从)
It was twelve o'clock when we arrived there．(when引起时间状语从句）
It was at twelve o'clock that we arrived there．（that 引起强调句）
3. it，one，that 的区别：作为代词，这三个词的对比使用是高考的热点之一。
NMET2000，23．
---Why don't we take a little break? ---Didn't we just have __________?
A．it B．that C．one D．this