“ do you exercise?” “Three times a week. ” A. How longB. How often C. How farD. How many

问题补充：

“ do you exercise?” “Three times a week. ”

A. How long

B. How often

C. How far

D. How many

答案：

A. How long

(答案→)B. How often

C. How far

D. How many

解析：How long多长；How often多久一次；How far多远；How many多少个。根据下文，一周三次。可知上文问的是，你多久锻炼一次？故选B。