--- do you watch TV?
---Only once on Saturday evening. You know as a student I am too busy.
A. How much
B. How long
C. How soon
D. How often
网友回答
A. How much
B. How long
C. How soon
(答案→)D. How often
解析：How much多少钱；How long多长；How soon多久；How often多久一次。根据下文，只在周六晚上一次。可知上文提问频率，故选D。