--- will your head teacher return from the USA?
---In two days.
A. How long
B. How soon
C. How often
D. How old
网友回答
A. How long
(答案→)B. How soon
C. How often
D. How old
解析：此题答案错误，短语辨析。How long 多长时间，How soon 多久，表示将来How often 表示频率，多久一次，How old 多大，in +时间表示将来，常用来回答以how soon提问的特殊疑问句。所以选B。