On

The book is on the table.

She left her keys on the kitchen counter.

Above

The plane flew above the clouds.

There is a painting above the fireplace.

Over

The bridge spans over the river.

They are having a picnic over there.

这些例句分别展示了"on"、"above"和"over"在不同情境下的用法，希望对你有所帮助。