taking a boat to school___a lot more fun than taking a bus为什么填must have 不填must be

问题描述:

taking a boat to school___a lot more fun than taking a bus
为什么填must have 不填must be

都可以

fun 是名词 have fun be funny

have fun to do sth是固定搭配,意思是做某事有意思
用be的话应该是be funny