I answered "I had a beer", and DL marked this as incorrect. Americans tend to say "can I get a beer?", whereas in Britain one would normally say "May (or can) I have a beer?". To quote an example from my Greek-English dictionary (D N Stavropoulos), "Θα πάρω ένα κονιάκ", "I'll have a brandy". I therefore think that "I had" (past tense) should be accepted. I have reported it.