问题补充：
— do you go home to see your parents ?
— Twice a month.
A. How often
B. How long
C. How far
D. How old
答案：
(答案→)A. How often
B. How long
C. How far
D. How old
解析：A. How often多久一次，表示频率B. How long多长时间，C. How far多远的距离 D. How old多大年纪；句意：你多久回家看你爸爸妈妈一次？一个月两次。故选A
