It takes them about (two hours) to get to the bus station.（对括号中的句子提问）
问题描述：
It takes them about (two hours) to get to the bus station.（对括号中的句子提问）
答
how long does it takes them to get to the bus station
答
How long does it take them to get to the bus station?
two hours表示时间长短,用how long提问.