— Peter do you visit your grandparents?— Twice a month.A. how long B. how soonC. how fa

问题补充：

— Peter, do you visit your grandparents?

— Twice a month.

A. how long

B. how soon

C. how far

D. how often

答案：

A. how long

B. how soon

C. how far

(答案→)D. how often

解析：

这题考查疑问词的用法：how long多久how soon多快how far多远how often多久一次，根据答语：一个月两次，选D。