4. 否定结构的倒装语序

我们有时为了强调而把否定词和词组放在句首，这时句子结构应倒装。例如：

1) On no account should we follow blindly.我们决不应当盲从。

2) No where has the world ever seen such great enthusiasm for learning as in our country.没有任何其他地方有我国这样高的学习热情。

五、 含有it的结构

考生病句：

1. As is known to all of us that science and technology play an important role in the development of society.

2. It is known to us, practice makes perfect.

正确表达：

1. It is known to all of us that science and technology play an important role in the development of society. (或：As is known to all of us, science...)

2. It is known to us that practice makes perfect. (或：As is known to us, practice.。。)

评议与分析：

例句1是93年12月六级考试11分作文的评分样卷句子，例句2选自97年1月四级考试作文。很显然，两个考生混淆了it和as的用法。如果用 it作形式主语，后面的主语从句必须由that引起;如果用as，则后面不能用that，因为as是关系代词，代表practice makes perfect。

It 在英语中是个相当活跃的代词，在写作中我们常要使用它。以下几种用法应熟练掌握，并能灵活运用。