简单英语问题It'stwohours'walk.=It'satwo-hourwalk.为什么前面的不要加a,后面的要加?翻译：goontodogoonwith

Question

简单英语问题
It's two hours' walk.=It's a two-hour walk.为什么前面的不要加a,后面的要加?
翻译：
go on to do
go on with

Answer 1

It's two hours' walk.=It's a two-hour walk.
two hours' 是形容词,是hours是复数,所以不加；
two-hour也是形容词,可以用a或an 修饰；
这是语言习惯,要死记.
go on to do sth.继续着手做,表示一件事情做了一半,中间中断后继续做这件事情；
go on with sth.就是继续做某件事,后面要加名词.