"Does he have the cold?"
Translation:A bheil an cnatan air?
Except that "the cold" IS normal in Scotland. We say here "I have the cold" in the same way native English speakers from outside of Scotland would say "I have the flu".
I have never (personally ofc) heard non-Scots say "I have a flu", only ever "the flu", and we use that same structure for colds. But if a Scot in Scotland were to say to another Scot "I have a cold" it would not strike the other as peculiar (i.e. they're interchangeable).
Outside of Scotland I have definitely heard it described in full as "the common cold" and never once as "a common cold". That I assume is wrong in all areas?
I think Duo needs to accept both, ofc, since they aren't just catering to Scots.
That being said, I have had to learn a number of Americanisms to avoid being penalised on the French course for English speakers! So until Duo fixes it and accepts both, users might just have to learn this common expression (dare I say "Scotticism").