on和over的区别如下：
指代不同、用法不同、侧重点不同。on是指在…上；over时指部分或全部覆盖在…上面。on指与另一物表面相接触；over指一物在另一物的垂直上方，多暗示悬空，但也含覆盖于……之上之意。
on造句
1、On the contrary, say defenders of pizza, it is indeed a healthful food.相反地，为披萨辩护的人则说它确实是一种健康食品。
2、Studies on TLC Identifications of Zhanjin Tincture展筋酊薄层色谱鉴别研究
3、He said something very absurd and we took him up on it.他说了一些非常荒廖的话，我们都责备他。
4、The principal has requested all teachers to circumscribe failures in red on the report cards.校长要求所有老师把成绩单上不及格的人用红笔圈起来。
over造句
1、Happiness diffused all over the crowded deck like a flower fragrance.幸福象花儿的芬芳一样散布在拥挤的甲板上。
2、not deny a person the chance to turn over a new leaf不绝其自新之路
3、They were a very good team, but they couldn't get over the hump.这是一直非常出色的球队，可惜总是不能迈过最后的门槛。
4、He stumbled over a stump and fell flat on his face他给树桩一绊，摔了个嘴啃泥。