at the corner 在拐角处
There's a grocer's at the corner of the street.
在街转弯处有一个食品杂货店.
Turn left at the corner.
在拐角处向左拐.
on the corner 的角落
There is a public convenience on the corner of the street.
在街道的拐角处有公共厕所.
The house is on the corner; you can't miss it.
那房子就在拐角处; 你不会找不到的.
in the corner 在角落里
They were chatting (away) in the corner.
他们在角落里闲谈.
She sat in the corner,watching my every move.
她坐在角落里注视著我的一举一动.
主要是地方不同,所用的介词就不同!