同学你好，该知识点来自沪江网校《新概念英语2、3册连读【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好：
这里用which 也是可以的。
which 和as 都可以指代前面整个句子，在从句中做主语/宾语。
这个句子作为例句出现时，其中用的是as。

参考以下——
关系代词as和which引导的定语从句
as和which引导非限制性定语从句，有相同之处也有不同之处。具体情况是：
1、as和which都可以在定语从句中做主语或者宾语，代表前面整个句子。
(1) He married her, as/which was natural.
(2) He was honest, as/which we can see.

2、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。

(1) As is known to all, China is a developing country.
(2) He is from the south, as we can see from his accent.
(3) John, as you know, is a famous writer.
(4) He has been to Paris more than severa l times, which I don’t believe.
注意：当主句和从句存在逻辑上的因果关系时，常用which。
(5) Tom was always late for school, which made his teacher angry.

3、当先行词受such, the same修饰时，常用as
(1) I have never heard such a story as he tells.
(2) He is not such a fool as he looks.
(3) This is the same book as I lost last week.
注意：当先行词由the same修饰时，偶尔也用that引导定语从句，但是和由as所引导的定语从句意思不同
(4) She wore the same dress that she wore at Mary’s wedding.
她穿着她在Mray婚礼上穿过的一条裙子。
(5) She wore the same dress as her young sister wore.
她穿着和她妹妹所穿的一样的裙子。

注意：定语从句such…as …与结果状语从句such… that…的区别：as在所引导的定语从句中作主语，宾语；that在结果状语从句中不做成分
(6)He has such a good laptop as I want to buy.
(7)He has such a good laptop that I want to buy one.

祝学习愉快～