—have you been married? —For twenty years.A. How far B. How oftenC. How longD. How soon

问题补充：

—have you been married?

—For twenty years.

A. How far

B. How often

C. How long

D. How soon

答案：

A. How far

B. How often

(答案→)C. How long

D. How soon

解析：How far多远；How often多久一次；How long多长；How soon多久。根据下文，大约二十年了。可知上文问的是时间长短，故选C。你们结婚多长时间了？