"My parents drink coffee."
Translation:Οι γονείς μου πίνουν καφέ.
Because the final "ε" in 3rd plural verb forms is optional. You can say "πίνουν" or "πίνουνε", "βλέπουν" or "βλέπουνε", "τρων" or "τρώνε", etc. :-)
I think the form with te final "ε" is especially used in oral discussions
My parents, object. Πίνουν, verb. Το καφέ, object, accusative form.
In ancient Gk I think this word is usually plural and is the same (e.g., Luke 2:43). That's kind of obvious, but I mention it because I think the singular is different now, γονέας, whereas in koine the sg was γονεύς. Without geeking out too much here, I wonder if the difference is that ancient people thought the male was the progenitor (sperm = tiny baby), whereas later women were seen as having a huge role other than just carrying the man's seed. Against that idea is that grammatical gender doesn't work on the basis of culturally derived notions of biological gender. Anyway, nowadays some people are single parents and so I'm guessing it is more common to refer to being "the parent" of a child.