关于非限定定语从句，which引导的能修饰单个名词，名词词组，分句，整句；而as引导的非限定定语从句只能修饰整个句子，对吗
1. 除去网友说的几种状况外，which 还可以指代主句中作表语的形容词或形容词词组。比如：
He was notsick, which some of the other passengers were.
他没生病，但有的其他旅客却病了。
（which 指代形容词 sick）
She is always careless, which we should not be.
她一直粗心大意，大家可不应该如此。
（which 指代形容词 careless）
The two policemen were completely trusted, which in fact they were.
那两个警察完全遭到信赖，事实上，也真是这样。
（which 指代形容词短语 completely trusted）
She was very patient towards the children, which her husband seldom was.
她对孩子们非常耐心，她老公却极少如此。
（which 指代形容词短语 patient towards the children）
2. 关于 as 能否引导非限制性定语从句，现代语法跟传统语法看法不同。最明显的一点是，as 引导的从句可以放在主句之前，还能叫定语从句吗？哪有在主句前的定语从句？不符合逻辑。应该叫比较从句。比如：
As we all know, he is a good basketball player.
