问题补充：
-----does your brother watch TV?
-----Every Saturday and Sunday.
A. How many
B. How often
C. How much
D. How long
答案：
A. How many
(答案→)B. How often
C. How much
D. How long
解析：句意：——你的哥哥多久看一次电视？——每周六和周日。A. How many 多少，多数量提问；B. How often多久，对频率提问； C. How much 多少，对价钱提问；D. How long多长时间，对时间段提问。根据Every Saturday and Sunday.可知是每周的周六和周日看电视，这是频率。故选B。
