Swimming in a pool is different from swimming in the sea because pools have clear water and no waves. Pools are also usually warm, so they're comfortable to swim in all year. The sea, on the other hand, has waves and tides, and you can see fish and other sea animals.
在泳池中游泳与在海中游泳是不同的,因为泳池的水清澈且没有波浪。泳池通常也很温暖,所以全年都适合游泳。另一方面,海洋有波浪和潮汐,你可以看到鱼和其他海洋动物。