The factory­­­­­­ we visited yesterday was the one I once worked.

问题补充：

The factory­­­­­­ we visited yesterday was the one I once worked.

A. where; which

B. which; which

C. which; where

D. where; where

答案：

A. where; which

B. which; which

(答案→)C. which; where

D. where; where

解析：句意：我们昨天参观的那家工厂是我曾经工作过的工厂。第一空位于先行词The factory­­­­­­后的定语从句中及物动词visit后缺少宾语，因此用关系代词that或which来代指。第二空后的定语从句中不及物动词work后不接宾语，因此用关系副词where来代指地点状语。故选C。