Barack Obama delivered a speech to 500 local youths during his visit to China many of we

问题补充：

Barack Obama delivered a speech to 500 local youths during his visit to China, many of were from Fudan University and Tongji University.

A. them

B. whom

C. which

D. those

答案：

A. them

(答案→)B. whom

C. which

D. those

解析：考查定语从句。根据先行词500 local youths可知当前面有介词是指人的引导词只能使用whom，故选B。