boy → buoy

buoy [bɔɪ] 与boy同音，作为名词是“浮筒，浮标”，作为动词是“使上浮，鼓励”——buoy the boy playing with a buoy，鼓励那个玩浮筒的男孩。

例句：The very salty water buoyed her (up) as she swam. 她游泳时，含盐量非常高的水使她漂浮了起来。（剑桥词典）