关系副词:不做任何的成分, 不够成从句的 核心成分，只是做 时间、地点、原因等状语.
when/where/why
Do u remember the day when he came to see u?
Do u remember the day that/which we spent in the woods?
定语从句的黄金法则
缺成分： 关系代词
不缺成分： 关系副词
1. 地点副词
This is the house where===(in which) he lived(不及) last year.
This is the house which he lived in last year.
This it the house that he visited(及) last year.
抽象地点
You have reached the point where a change is need.
case/point/position/situation/stage/state
2.时间副词
Almost everyone can remember the day when=== on which he was born.
I still remember the days that/which/空 we spent in that country.
3.原因副词
I know the reason why he did that.
I konw the teason that/which/空 he explianed at the meeting.
关系副词的省略
when : the time/day/occasion
where : place/room
why : reason
This is the factory where/in which he worked.
I remember the day when/on which he left.
The reson why/for which I was late is the traffic.
介词+where/when 引导的定语从句
He stood on the top of the tower, form where he could see the whole city.
I bought this house 5 years age, sice when things have gone better.