will he be back?In a week.　A. How long B. How soon C. How oftenD. How many

问题补充：

will he be back?

In a week.

A. How long

B. How soon

C. How often

D. How many

答案：

A. How long

(答案→)B. How soon

C. How often

D. How many

解析：How long多长；How soon 多久；How often多久一次；How many多少个。根据下文，一周后。可知上文提问未来时间，故选B，他多久回来？