— do you exercise?— Twice a week.A. How longB. How manyC. How oftenD. How soon

问题补充：

— do you exercise?

— Twice a week.

A. How long

B. How many

C. How often

D. How soon

答案：

A. How long

B. How many

(答案→)C. How often

D. How soon

解析：How long多长;How many多少个;How often多久一次;How soon多久. 根据下文,一周两次. 可知选C,你多久做一次锻炼?