非限定性定语从句中 as引导非限制性定语从句,若as在从句中作主语,其引导的句子可以放在句首,也可以放在句中.但whic

As is known to all,the more you pay,the more you'll get.正如所有人都知道的,你付出越多,收获也就会越多.
这里as在从句中作主语引导非限制性定从来修饰后面的主句.
如果这里换成which来写的话,就只能写成如下方式：
The more you pay,the more you'll get,which(as) is known to us all.
此时的which引导的从句是不可放在句首的.而句中的which是可以用as来替换的,所说的就是这个意思吧.这一般就是提醒你在做题或写作时注意which引导的非限制定从绝对不可以放在句首.
纯手打...好累,

As we know, smoking is harmful to one's health.
The sun heats the earth, which is very important to us.