Question

This is the city _____ I visited 10 years ago. A. where B. which C. who D. that 选哪一个，为什么？

Answer 1

选B/D。visit后面缺宾语 visit+某地，即the city
用that/which来代替。

Answer 2

选A
这是个定语从句， 先行词为the city , 在从句中做地点状语，所以需要一个关系副词where，where相当于in which。