"I need some pretty dresses for the party."
Translation:Yo necesito unos vestidos bonitos para la fiesta.
i did the same without "yo" and it was accepted. it should definitely be accepted with "yo" included though.
A copy-paste of my answer which was accdpted:
Necesito algunos vestidos bonitos para la fiesta.
They must have fixed it.
Yes, my answer also and it was accepted, with the note that unos is also correct.
Why? What's wrong with it? And why is it being accepted now it it's wrong?
Unos means some (masculine) while usar is to wear or to use. I think it does not use usar because the original sentence does not talk about wearing dresses.
A matter of "I need to wear some pretty dresses for the party" vs "I need pretty dresses for the party."