问题补充:
--- Jenny, do you visit your grandparents?
--- Twice a month.
A. How long
B. How soon
C. How often
D. How many
答案:
A. How long
B. How soon
(答案→)C. How often
D. How many
解析:A. How long多长时间 B. How soon 多久 C. How often多久一次D. How many多少;句意:珍妮,你多久去看望你的祖父母一次?一个月两次。故选C