swim是动词，而swimming则是名词，表示游泳这项运动。而swim的现在进行时同样是swimming，不要把它和作为名词的swimming搞混了。
swim
1、She swam the 400 metres medley ten seconds slower than she did in 1980.
她400米混合泳的成绩比其1980年慢了10秒。
2、The barriers are lethal to fish trying to swim upstream.
这些障碍物对于想要往上游游动的鱼儿来说是致命的。
3、Alexis suddenly could take no more: he felt too hot, he couldn't breathe, the room swam.
亚历克西斯突然觉得受不了了，他感到闷热，喘不上气，仿佛整间屋子在旋转。
4、The musty aroma of incense made her head swim.
熏香发霉的气味令她感到头晕。
swimming
1、Swimming is probably the best form of exercise you can get.
游泳或许是现有的最佳锻炼方式。
2、There was swimming and sailing down on the lake.
有人在湖上游泳和扬帆。
3、She teaches swimming, lifesaving and water aerobics.
她教授游泳、救生术和水中有氧运动。
4、We went swimming very early
我们很早就去游泳了。
5、If the tide was in they went swimming.
如果涨潮了，他们就去游泳。
