问题补充：
—Could you tell me ?
—About two hours.
A. how long it takes to fly to Guilin
B. how long it took to fly to Guilin
C. how long does it take to fly to Guilin
D. how long did it take to fly to Guilin
答案：
(答案→)A. how long it takes to fly to Guilin
B. how long it took to fly to Guilin
C. how long does it take to fly to Guilin
D. how long did it take to fly to Guilin
解析：句意：你能告诉我飞往桂林要花费多长时间吗？大约两个小时，宾语从句用陈述句的语序，it takes sb some time to do sth某人花费多长时间做某事，故选A
