— have you been in the sports club?—Since the first month I came to the schoolA. How oldB

问题补充：

— have you been in the sports club?

—Since the first month I came to the school．

A. How old

B. How long

C. How much

D. How soon

答案：

A. How old

(答案→)B. How long

C. How much

D. How soon

解析：How old多大；How long 多长；How much 多少钱；How soon 多久一次。根据下文，自从我来到这个学校的第一个月。可知上文问的是时间长短，故选Ｂ，你加入这个运动俱乐部多久了？