as引导的定语从句

Question

as能不能引导限定性定语从句？若能求用法

Answer 1

同学你好，引导状语从句的连词as可以用作关系代词，引导定语从句，因而被称作准关系代词。
1. 准关系代词as引导限制定语从句，用于以下3个结构中，as在从句中作主语、宾语或表语：
a. so / such…as
Such people as were mentioned by him were honest. (as作主语)
I’ve never seen such a clever man as he is. (as作表语)
Last term our maths teacher set so difficult an (= such a difficult) examination problem as none of us worked out.
b. the same…as
Modern statemen are often faced with the same problem as defeated the ancient Romans. (as 作宾语)
I like the same book as you do. (as 作宾语)
c. as…as
As many children as came were given some cakes. (as 作主语)
He is as diligent a man as ever lived. (as 作主语)
补充：
a. such…as 与 such…that的区别
such…as 引导定语从句；such…that引导结果状语从句。
They talked in such simple English as children could understand.
他们用孩子们能听懂的简单的英语交谈。
They talked in such simple English that children could understand it.
他们用十分简单的英语交谈，连孩子们都能听懂。
I will provide you with such things as you may need.
我要供给你一些你可以用得着的东西。
He shut the window with such a force that the glass broke.
他如此用力地关门，结果玻璃碎了。
b. the same…as与the same…that的区别：
the same…as指两物相似，the same..描述的是同一物。
This is the same bag as I lost yesterday.
这个书包和我昨天丢失的（书包）相似。（相似物）
This is the same bag that I lost yesterday.
这正是我昨天丢失的那个书包。（同一物）

Answer 2

as在定语从句中是关系代词，可做句子成分。但在上述两个句子中，as只是在引导定语从句而已，不作句子成分。
as
引导非限制性定语从句，可放在主句之前，或者主句之后，甚至可以切割一个主句；which引导的非限制性定语从句只能放在主句之后。另外，as有“正如……，正像……”的意思

Answer 3

as引导定语从句，限制性和非限制性，有先行词
定语从句一定要有先行词
what
不能引导定语从句