— will you come back Mum?—In ten minutes.A. How longB. How soon C. How oftenD. How far

问题补充：

— will you come back, Mum?

—In ten minutes.

A. How long

B. How soon

C. How often

D. How far

答案：

A. How long

(答案→)B. How soon

C. How often

D. How far

解析：How long多长；How soon 多久；How often多久一次；How far多远。根据下文，十分钟后。可知上文提问的是多久，故选B。