关系代词 一般作主语,宾语 关系副词作状语 I visit the factory where I worked ten years ago. where就是关系副词,在从句里作地点状语 where=in which,which代表factory I worked in the factoy ten years ago. I visit the factory which/that was built ten years ago. which,that 关系代词,代表factory factory was built ten years ago. 在从句里作主语
