burn的過去式和過去分詞？

　　burn的用法例句：

　　1.The power stations burn coal from the Ruhr region.

　　發電站燒的煤產自魯爾地區。

　　2.He was a high-earning broker with money to burn.

　　他是高收入的經紀人，有花不完的錢。

　　3.Watch them carefully as they finish cooking because they can burn easily.

　　就要做好時得小心看著，因為它們很容易燒糊。

　　4.Traditional slash and burn farming methods have exhausted the soil.

　　傳統的刀耕火種農業方式耗盡了土地的肥力。