-- dose it take to get to the airport from here ?
-- It takes half an hour.
A. How long
B. How soon
C. How far
D. How often
网友回答
(答案→)A. How long
B. How soon
C. How far
D. How often
解析：How long多长；How soon多久；How far多远；How often多久一次。根据答语，用了半个小时。可知上文问的是时间长短，故选A。