(六)as,which引导的非限定性定语从句
由as, which 引导的非限定性定语从句,as和which可代整个主句,相当于and this或and that。As一般放在句首,which在句中。
1)As we know, smoking is harmful to one's health.
2)The sun heats the earth, which is very important to us.