my teacher marked these phrases as wrong but i don't know what about them is wrong:

1. je revelerais sans prevenir
2. j'ai vendu mes robes plus jolies

both of them need "un mot a ajouter"

2 answers

Not sure but:

Je *me* revelerai sans... I will reveal *myself*... It's reflexive.

J'ai vendue mes robes les plus jolies. Can't explain it - it just sounds right.
Thank you for using the Jiskha Homework Help Forum. You have good help from Tony in that it could be reflexive OR have a direct-object involved. Somehow you need to "reveal/develop" SOMETHING.

#2 is no doubt saying "I sold my prettiest dresses." + J'ai vendu mes robes les plus jolies. (Just check the past participle.)

Mme