under与below的区别.如on与over,on与之接触,而over有一定距离

under强调空间上的直上直下,如,under the desk is there a cat.；below 只是强调平面上的相对上下位置,如,below the picture on the wall is there another picture.below 还可以指抽象的在.以下,如below zero
under的意义更广一些,还有‘掌管、管辖’等之意.如,under the leadership of the government.