swim: “游泳”最普遍的说法
splash around = splash about: 在水里面嬉耍，拍打着游水
go for a paddle: 在海边涉水，趟水
take a dip ＝ go for a dip: a quick/brief swim 小游一会儿，游两圈
do some lengths: 游几个来回

It's so hot today. I'll go for a swim in the afternoon.
今天真热,我下午去游个泳.
The babies have a good time splashing about in the swimming pool.
小宝宝们在泳池里玩水。
The water splashed about in the bucket.
这个水在桶里面到处晃来晃去飞溅出来。
We live right next to the beach, so we can go for a paddle anytime we want.
我们就住在沙滩边，所以想什么时候去海边游游水都可以。
Let's take a dip in the lake. The temperature is perfect.
我们去湖里小游两圈吧，温度正合适。
She did a couple of lengths in the swimming pool and she's short of breath.
她在泳池里游了几个来回，现在有点气短。