i visited the school where i had my best memories.我想问had 是及物动词,那为什么连接词不是用关系代词which呢?

问题描述:

i visited the school where i had my best memories.我想问had 是及物动词,那为什么连接词不是用关系代词which呢?
at which 不是关系副词吗?

要用which的话需要加介词 at which