— Mr. Smith joined in different activities in Beijing. Do you know ?— Since 5 years ago.A.

问题补充：

— Mr. Smith joined in different activities in Beijing. Do you know ?

— Since 5 years ago.

A. when he went there

B. how long he has stayed there

C. how soon he will come back

D. when he will come here

答案：

A. when he went there

(答案→)B. how long he has stayed there

C. how soon he will come back

D. when he will come here

解析：句意：史密斯先生在北京参加了不同的活动。你知道他在那儿呆多久了吗？自从5年前。根据答语Since 5 years ago可知该选B。