"She writes some new recipes."
Translation:Elle écrit de nouvelles recettes.
Wouldn't "Elle écrit des nouvelles recettes" work as well since she's writing some recipes plural?
It seems to be a new feature that Duo now tells you this if you get it wrong. Bravo!
I believe that adjectives like "nouvelles" just need to be in front of the noun.
Suppose she is a professional cook writing brand new recipes. Then how about the following?
Elle écrit des recettes neuves.
Something "neuf, neuve, neufs, neuves" is usually something you can buy. If she writes recipes or other book, or if whoever produces a piece of art or works of imagination, you will use "nouveau, nouvel, nouvelle, nouveaux, nouvelles".
What about "quelques unes" when we use it, and it's wrong to say "elle écrit quelques unes nouvelles recettes"
"quelques-unes" is a pronoun, so you cannot use it as an adjective to modify a noun:
- elle écrit quelques nouvelles recettes = she writes a few new recipes
- elle en écrit quelques-unes = she writes a few of them.