I will swim
I'm going to swim (úmysl)
I'm swimming (arranged future)
I swim tomorrow ( timetable)
I will have swum (by next sunday)
By next year I'll have been to Africa.
By the time, you come, I'll have seen the movie.
Decision now - I'll answer the phone.
promise, offer - I'll cook for you.
I think, I know, I hope, I predict