那要看你是想表达什么意思呢。
over/above/ on 都可以表示“在......上之意。具体区别:
over:长表示恰好垂直的位置关系,或者含有空间上接近的含义。其反义词为under.如:
There is a bridge over the river.
My pen is now under your desk.
above:只笼统的表明“高于......;在......之上”,多指在相对较高位置。其反义词是below。如:
We flew above the clounds.
表示“高于某个抽象水平”或“温度zero degree以上多少度”用above。
His work is well above the average.
The temperature is three degrees above zero.
【The temperature is above/over 30 "C.温度高于...时可互用。】
on:"...表面上”,强调与表面接触。其反义词为beneath[正式语体,现代英语中多用比喻义。如:
There are some books on the desk.
The village was situated beneath a wooden hill.村庄位于林山下。
As a scholar,he is far beneath his brother.
另外,能力上超过,在谁之上,也可以用beyond
参考资料:http://zhidao.baidu.com/question/253054288.html