问题补充：
---Do you know it is from our school to Yangzhou?
---I am not sure. I guess its about 40 minutes by bus.
A. how far
B. how soon
C. how long
D. how often
答案：
(答案→)A. how far
B. how soon
C. how long
D. how often
解析：句意：--你知道从我们学校到扬州多远吗？--我也拿不准，我猜坐汽车需要40分钟。A. how far多远； B. how soon多久； C. how long多长； D. how often多常。根据句意故选A。
考点: 考查疑问词辨析。
