I think it must be very interesting to travel around the world.

问题描述:

I think it must be very interesting to travel around the world.
But it costs__much money and sometimes it is full of danger.
A.one B.two C.three D.four

选择A
此处是one是代词,相当于someone、somebody.
eg To finish study English well ,one should study hard.
本句也符合句型 it costs sb.some money
供参考.