I still remember the park I visited in London years ago.A. whatB. whoC. thatD. when

问题补充：

I still remember the park I visited in London years ago.

A. what

B. who

C. that

D. when

答案：

A. what

B. who

(答案→)C. that

D. when

解析：句意：我仍然记得我几年前在伦敦参观过的那个公园。What不能引导定语从句，when在定语从句中不能作宾语；这里是一个定语从句，先行词是park，在定语从句中作宾语，所以用which/that来引导，故选C。