题目内容：

A train is fast.A bus is slow.But is doesn't cost___much.A too B very C the

优质解答

我认为是B
首先C不对,没有这么用的,如果是that还可考虑
而A too 是含有贬义,一般用为too...to...表示 太...以致不能...
所以只有B比较合适了.
楼主的句有个词一定错了.全句应为：
A train is fast.A bus is slow,but it doesn't cost very much.