---You look very healthy. do you exercise?---I exercise three times a week. A. How ofte

问题补充：

---You look very healthy. do you exercise?

-----I exercise three times a week.

A. How often

B. How many

C. How much

D. How soon

答案：

(答案→)A. How often

B. How many

C. How much

D. How soon

解析：How often多久一次；How many多少个；How much多少，提问不可数名词；How soon多久。感觉下文，我每周联系三次。可知上文问的是，你看起来很健康，你多久锻炼一次？故选A。