swim是动词，而swimming则是名词，表示游泳这项运动。swimmer（游泳者）

例句：

You don't have to worry about me. I'm a good swimmer

你不用担心我。我水性很好。

He is swimming right now.---她现在在游泳。

My hobbies are painting and swimming.---我的兴趣bai是画画和游泳。