導語：定語從句，一個簡單句跟在一名詞或代詞後（先行詞）進行修飾限定，就叫做定語從句。在主句中充當定語成分。被修飾的.詞叫先行詞。定語從句不同於單詞作定語的情況，它通常只能放在被修飾的詞（即先行詞）之後。下面是由小編爲你整理的定語從句裏as用法，歡迎大家閱讀。
由as,which 引導的非限定性定語從句,as和which可代整個主句,which相當於and this或and that.
1)As一般放在句首,which在句中.
2) as也可在句中往往和see,know,expect等詞連用.
seemed not to have grasped what I meant,which/and this greatly upsets me.
sun heats the earth,which/and this is very important to us.
was expected,the beautiful girl married a handsome boy.
we all know,smoking is harmful to one's health.
must be from Africa,as can be seen from his skin.
定語從句中若先行詞前有the same,such作修飾語,通常用as作關係代詞.
He used such expressions as he could find in the texts.
They stayed for the night in the same room as they had once rented.
such…as和
such…as定語從句,as在從句中可以作主語,賓語,表語；such…that引導結果狀語從句,that不充當任何成分,只起到連接作用,如：
They talked in such simple language as children could understand.
They talked in such simple language that children could understand it.
the same…as和the same…that
兩者都可以引導定語從句,但the same…as指兩件事物,而the same…that指同一件事物：
He is using the same pen as I did 10 years ago.
他用的這支鋼筆和我十年前用的那支一個樣.
He is using the same pen that I did 10 years ago.
他用的這支鋼筆就是我十年前用的那支.
