- does your cousin exercise? ---Three times a week.A. How manyB. How oftenC. How longD.

问题补充：

--- does your cousin exercise? ---Three times a week.

A. How many

B. How often

C. How long

D. How much

答案：

A. How many

(答案→)B. How often

C. How long

D. How much

解析：句意:--你表弟多长时间锻炼一次？--一周三次。A. How many多少次； B. How often多久一次； C. How long 多长； D. How much多少。根据句意故选B。