------ does your father surf the Internet?
------once a week.
A. How many times
B. How long
C. How often
D. How soon
网友回答
A. How many times
B. How long
(答案→)C. How often
D. How soon
解析：How many times多少次；How long多长；How often多久一次；How soon多久。根据答语，一周一次。可知上文提问频率，故选C。