"Hello and goodbye."
Translation:Γεια σας και αντίο.
Γεια σας και γεια σας would sound really odd in Greek though. It's almost like saying "Hello and hello" or "goodbye and goodbye" in English, since it's the same word, being repeated. The only case that someone could say γεια σας twice in the same sentence, is if there was someone kind of distinction between the two, or if the speaker greeted two different people or groups. ^.^
Γεια σας! I know this isn't a grammatical problem but when asked to form a Greek sentence from "pieces with audio", I often can't hear the first word. Here it's "Γεια".
I've reported it many times, now as well, probably some typical error on the audio programm. Not a big loss, but hopefully will get fixed some day :-)
Αντίο και "Χάππι λέαρνινγ"!