emmm，刚在看“介词+关系代词”引导的定语从句这一语法，没看懂那个“介词”要什么时候参考先行词的介词短语，或什么时候要参考从句动词的介词短语。麻烦各位大大指教一下QAQ
1. 介词+关系代词=关系副词when/where。若先行词是时间名词，介词就应该是表示时间的介词；若先行词是地点名词，介词就应该是表示地点的介词。至于用哪个介词，这要看句意和前面的先行词。如;
This is the house where(=in which)he once lived.
There is a table where(=on which) lies a map of China.
There is a farm where(=on/at which) lived 50 people.
I'll never forget the day when(=on which) I joined the Party.
We will always remember the days when(=in which) we worked together.
June 4th is her birthday when(=on which) she will invite all her friends to her birthday party.
He died from a traffic accident at 6:30 am, when(=at which) we were sleeping.
2. 介词提前时，要看句子的动词：是及物动词还是不及物动词，以及动词与介词的搭配。如：
I know the boy with whom you will go.
The man to whom you referred is my uncle.
注意：动词短语是固定搭配,不可分割时,那么动词短语的介词一般不能提前，如look after,look for, take care of, hear of, hear from等。
The man whom/who she is looking after is her daddy.