En lys, et lys.....interchangeable?
No, but you could use "lys" meaning "fair" or "bright", such as "Det er en lys dag" (It's a bright day).
No. "Et lys" means "a light." "En lys" does not make grammatical sense.
Would I be right in thinking that you would only use 'en' and 'lys' together when using the latter as an adjective? EG, 'gul er en lys farge'?
To me this sounds like "Skinner månens med lys" during listening comprehension.
I've heard stuff like this cannot be fixed but it was quite confusing anyhow...
En lys dag Because it's an adjective, and it follows the gender of the noun. Dag is a masculine noun, so...
Duolingo Audio: The stress must be on the first syllable of the presense verb "skinner" or else it will mean railwail trails ( if pronounced as a noun)!