-- does your sister practice singing English songs?----Twice a week.A. How soonB. How long

问题补充：

-- does your sister practice singing English songs?

----Twice a week.

A. How soon

B. How long

C. How far

D. How often

答案：

A. How soon

B. How long

C. How far

(答案→)D. How often

解析：根据回答一周两次，可知问多久又一次，A多久以后B多长时间C多远D多久一次，故选D