I’ve always found it difficult to say certain things in English at the gym properly, here are a few of them:
Can I do a set/ Can we share the bench/ Can we alternate/ Can we take turns? - when someone’s using an equipment that you want to use.
Yes I’m using it but we could share/alternate/take turns if you want- when you want to let someone know that he can use the equipment you’re using.
No you finish your set, I need to add more plates- when you someone’s offering you to share an equipment with them but you want to let them know that you’ll workout with much heavier weights and that’s why you want them to finish first.