其实啊，昨天分享的“3个句式、2个注意”只是as引导限制性定语从句，人家还可以引导非限制性定语从句呢！厉害吧，那引导这种从句又有哪些知识点呢，且听小编我慢慢道来。

as引导非限定性定语从句时（有逗号隔开），只能修饰整个主句。

1). 可置于主句之前、之后或主谓之间，翻译成“正如...那样”。例如：

As we all know, the earth moves around the sun. (从句位于主句之前）

The earth moves around the sun, as we all know. (从句位于主句之后）

The earth, as we all know, moves around the sun. (从句位于主谓之前）

2). 在非限制性定语从句中，which和as的区别：

a. 位置：

as引导的从句可以放在主句前、主句后、主谓之间；

which引导的从句不能放在主句前。

As is known to all, he is the best student in our class. （✔️）

Which is known to all, he is the best student in our class. （✖️）

As was expected, he succeeded at last. （✔️）

Which was expected, he succeeded at last. （✖️）

b. 含义：指代一个句子时，as是“正如/就像”之意；which是“这/这件事”之意。

常见句式：

as is said above 正如上文提到的；

as is expected 正如大家所料；

as is known to all, 正如大家都知道的；

as is reported in the newspaper, 正如报纸上报道的；

As is said above, he studies very hard.

正如上文提到的，他学习非常努力。

Li Ming was late, which made Mr. Zhang very angry. 

李明迟到了，这件事让张先生很生气。

c. 介词后只能用which。例如：

He had studied computer for one year, after which he found a job in a big company. （✔️）

He had studied computer for one year, after as he found a job in a big company. （✖️）

Scientists have advanced many theories, none of which has been proved. （✔️）

Scientists have advanced many theories, none of as has been proved. （✖️）

小Tip：针对as/which引导的非限制性定语从句，考点有三：

1). as“正如”的常见句式；

2).as引导的从句可位于句首，但which不行；

3). 介词后只能用which，不能用as。

【摘自：百词斩】