-- Can you tell me --- to travel to Dalian?-- About two hours by plane.
a\ how much it costs
b\ what l should takes
c\ how long it takes
d\ which is the best season
答案：C
解析：how long（多久） 对应后面的two hours （两小时）
中文：你能告诉我去大连要花多少时间?大概两个小时的飞机.