问题补充：
— will your father be back?
—In two months.
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：疑问代词辨析。how long 多长时间 how soon 多久才会 how often 多久一次 how many 多少（修饰名词复数）。根据答语“两个月后”可知问题“你爸爸多久才会回来？”故选B。
