around\on the edge of有什么区别?the government decided to build flats around the edge of the city.at that time,they had a small house on the edge of towm.为什么一个用on 一个用around?

around\on the edge of有什么区别?the government decided to build flats around the edge of the city.at that time,they had a small house on the edge of towm.为什么一个用on 一个用around?
around\on the edge of有什么区别?
the government decided to build flats around the edge of the city.
at that time,they had a small house on the edge of towm.
为什么一个用on 一个用around?

around\on the edge of有什么区别?the government decided to build flats around the edge of the city.at that time,they had a small house on the edge of towm.为什么一个用on 一个用around?
around ……的周围,围成一个包围圈.
on the edge of 在……的边缘,只是一个点.

on是说周围的某一边
around是说整个包围起来的圆圈