at the edge of...与on the edge of...

at the edge of...与on the edge of...
at the edge of...与on the edge of...

at the edge of...与on the edge of...
He is standing at the edge of the cliff.他站在悬崖的边上.强调在某一地点.
There is a knife on the edge of the table .桌边有把小刀.强调在某一平面上.

都有边缘，濒临边缘的意思
on the edge of 已经在边缘上了
at the edge of 濒临边缘，接近边缘