Question

Which引导的非限定定从，which只能做主语吗？

Answer 1

which在非限制性定语从句中可以作主语、宾语、表语。
先行词可能是前面的名词，也可能是整个句子。
如
He got up very late, which主语 made his father angry.先行词整个句子。

I went to visit the old house, which宾语 I used to live in.先行词: the house