I wrote "Have a tea" and was marked wrong. It seems like normal to me to say to someone in English "Have a tea" or "Have a coffee", like how we might say "I'd like a tea/coffee." So I have reported it. This is an explanation for why I reported it. Sometimes it would be nice if we could put a comment with our report, but that is a Duolingo programming thing, not something the Gaelic Duo team can do anything about.