above在上方,不确定的上方,较笼统
over在上方,垂直的上方,正上方
on在……上面,指在平面上,并与平面相接触
蝴蝶在花丛中跳舞The butterflies are dancing among the flowers.
蝴蝶正在花上跳舞The butterfly is dancing on/above/over the flowers .
蝴蝶在草地上跳舞The butterfly is dancing on the ground.