主语移至句子的后面。

　　1．代替不定式短语作形式主语

　　It is impossible to get there by boat.

　　坐船不可能到那里。

　　It's very kind of you to help me.

　　你帮助我真好。

　　2．代替动名词短语作形式主语

　　常用于以下结构中：

　　It's no use/no good/no fun/useless/a waste of time doing sth.

　　做某事没有用/没有好处/没有意思/没有用/浪费时间。

　　It is no use giving him some advice.

　　＝It is useless giving him some advice.

　　给他提建议没用。

　　3．代替主语从句作形式主语

　　It is necessary that the work should be done well.

　　这项工作应该被完美完成是必须的。

　　It's a pity that I didn't think of it earlier.

　　我没有早一点这么想真是遗憾。

　　4．注意以下固定句型

　　It seems(ed)/appears(ed) that ...　似乎......

　　It (so) happened that ... 碰巧......

　　It turns(ed) out that ... 结果是......

　　It occurred to sb. that ... 某人突然想起......

　　It is said/reported/believed/hoped/well­known/suggested ... that ...

　　据说/据报道/大家都相信/人人都希望/大家都知道/有人建议......

　　It so happened that the tickets were sold out.

　　碰巧票都卖光了。

　　It occurred to her that she might adopt a homeless child.

　　她突然想到她可以收养一个无家可归的孩子。

　　It turns out that the situation is quite serious.

　　结果表明情况很严峻。

　　[即时演练2]　补全句子

①(2015·四川高考满分作文)I badly need to improve my oral English, so it is great for me to find a native speaker to learn from.