shovel的过去式怎么变化

　　例句：

　　A shovel was leaning against the wall.

　　一把铁铲靠墙放着。

　　They went out in freezing conditions to shovel snow.

　　他们冒着严寒出去铲雪。

　　The children took their pails and shovels to the beach.

　　孩子们带着桶和铲子到海滩上去了。