理解PK: This is the house which we bought last week.翻译：
The house,which we bought last week,is very modern.翻译：
I have a girlfriend who works abroad.
I have a girlfriend, who works abroad.
He never wears clothes which make him look different.
He never wears clothes, which make him look different.
- As/which引导的非限制性定语从句: 先行词为整个句子时用。
You drove too fast,which was very dangerous.翻译：
As is known to all,driving too fast is dangerous.翻译：
He came back late, means he missed the TV show.