October 1st 1949 is the day the People’s Republic of China was founded. A. on whichB. i

问题补充：

October 1st, 1949 is the day the People’s Republic of China was founded.

A. on which

B. in which

C. that

D. which

答案：

(答案→)A. on which

B. in which

C. that

D. which

解析：考查定语从句。on which=when指代先行词在从句中做时间状语。