above同埋on

on --- had to be touching on the thing you're talking about.
example. The plate is on the table. (the plate must be touching the table)

above -- do'nt have to be touching on the thing you're talking about.
example. The clock was above the table. (the clock was above the table but it doesn't mean that it was touching the table.)

above:[物品1]在[物品2]的上面***[物品1]與[物品2]沒有任何接觸***

on:[物品1]在[物品2]的上面***[物品1]與[物品2]有接觸***

希望幫到你=]*