新人教版高二英语选修六it用法授课课件mdash;mdash;It的用法词.ppt

新人教版高二英语选修六it用法授课课件——It的用法词 知识要点 It的用法 （一）作人称代词 1、it代替前面（或后面）的单数名词或分句等所表示的事物。 e.g. You cannot eat your cake but have it.（it代替前面的cake） Although we cannot see it, there is air all around us. （it代替后面的air） They say he has left town, but I don’t believe it. （it代替前面They…town分句中的情况） 返回目录 知识要点 2、代替有生命但不能或不必分阴阳性的东西（包括婴儿）。 e.g. Yesterday we saw a big tree. It was fully twenty metres high. （it代替前面的tree） The baby cried because it was hungry. （it代替前面的baby） 返回目录 知识要点 3、在某些习惯说法中，可以代替人。 e.g. ---- Someone is knocking at the door, Peter. ---- Who is it? ---- It’s me. ---- Who are singing? ---- It is the children. ---- The light is still on in the lab. It must be the third-year students doing the experiment. 返回目录 知识要点 4、it与one的区别：这两个词都可以代表前面说过的名词，但it用于同名同物的场合；one则用于同名异物的场合。 e.g. ---- Do you still have the bicycle? ---- No, I have sold it. ---- Is this knife yours? ---- No. It is Xiao Zhang’s. Mine is the one on the desk. 返回目录 知识要点 5、it与that的区别：两词都可代替某一特定名词，但that指同一类，并非同一个。 e.g. The climate of South China is mild（温和的）; I like it very much.（it指the climate of South China） The climate of South China is much better than that of Japan.（that指the climate） 返回目录 知识要点 （二）作无人称代词 it作无人称代词时，除了句中找不到它所代表的词语外，另一个特点是它后面的内容都是表示天气、时间、距离、度量衡及情况等。 It is fine (rainy, windy, etc.). It is noon. It is a half hour’s walk to the factory. It is eighteen square metres in area. What does it matter? 返回目录 知识要点 （三）作强调词，构成强调结构 用以帮助改变句子结构，使句子的某一成分受到强调。“It is (was) + 所强调的成分 + that (who) + 其它成分。”在这个句型中，it本身没有词义。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。 返回目录 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 oclock when we arrived there．(when引起时间状语从句） It was at twelve oclock that we arrived there.（that 引起强调句） 返回目录 知识要点 （四）引导词it作形式主语（宾语） 为了使句子平衡，常采用形式主语（或宾语）it ，而把真正的主语（或宾语）置于句子后面。通常引导词it与它所代替的句子成分中间要夹有某些词。 e.g. It takes half an hour to go there on foot.（It与to go