.Do you know the year the Chinese Communist Party was founded? A. which B. that C. when D.

问题补充：

.Do you know the year the Chinese Communist Party was founded?

A. which

B. that

C. when

D. on which

答案：

A. which

B. that

(答案→)C. when

D. on which

解析：when是关系副词，表示时间，在定语从句中作时间状语。