请教一下复合句子的用法~~

这句应该是where。
再看看这一句： Is this the factory __that____you visited last week.
区别在于第一句的陈述句语序为This factory is THE ONE THAT (where)you visited last week.这是状语从句，而第二句的语序则为This is the factory that you visited last week.则为定于从句。