问题补充：
-- does it take you to get to school?
-- About twenty minutes.
A. How
B. How long
C. How many times
D. How often
答案：
A. How
(答案→)B. How long
C. How many times
D. How often
解析：How怎样；How long多长；How many times多少次；How often多久一次。根据下文答语，大约二十分钟，可知上文提问时间长短，故选B。
