如果你不会游泳，可以用 "I don't know how to swim" 来表示。这句话的来源是英语中 "know" 的含义是 "知道、了解"，"how" 表示 "怎样"，"to swim" 是 "游泳" 的意思。

例如：

I don't know how to swim. 我不会游泳。

Can you teach me how to swim? 你能教我游泳吗？

I'm afraid of the water because I don't know how to swim. 我害怕水是因为我不会游泳。