How many cities have you travelled to 中"to"可以省略吗?为什么?

问题描述:

How many cities have you travelled to 中"to"可以省略吗?为什么?

不可以.因为如果你把to省略掉了,还原成陈述句就成了:
i have travelled 5(个数)cities
没有travel city 这种搭配,travel 是不及物动词