—How often do the students play sports?A. Twice a dayB. Since last nightC. For two hoursD.

问题补充：

—How often do the students play sports?

A. Twice a day

B. Since last night

C. For two hours

D. A month ago

答案：

(答案→)A. Twice a day

B. Since last night

C. For two hours

D. A month ago

解析：考查疑问副词短语的答语。上文用how often（多久一次）提问，下文需是表频度的答语。故选A。twice a day“每天两次”。【易错分析】B项和C项常用于现在完成时，D项常用于一般过去时。