Translation:They are sitting on the bed and are listening to the music.
I put "They sit in bed and listen to music", but was marked incorrect and told "You need the article "a" here". Then correct solutions are given as:
• They sit in a bed and listen to music.
• They are sitting on the bed and are listening to the music.
The latter of which noticeably does not have the indefinite article - so much for "you need the article "a" here"; or does one only need the indefinite article if one shoots for "in" as the preposition rather than the literal "on"? If so, why?
Is there any relevant qualitative difference between "in a bed" and "in bed"? Because in English I can't find any (beyond that the former tells us they're in the same bed and the latter merely strongly implies it), and in Russian, it seems to be prepositional case either way, and as we know, the preposition need not be translated literally, so what's going on with this article?