How would you say "They know to swim". Would it be the same? I mean they technically have the same messing but I got it wrong for saying that so I just wonder what it would be.

Is 'como' just implied here (ex: sabe como nadar) or is this a bad Portuguese sentence.

It's hard to distinguish this exercise from "Ele sabe nadar"...

I'm also wondering how we'd write "they know to swim", as in they are aware that they should use the ability they have at some specific time.