In the sentence "tout le monde aide avec les corvées"
1. why is the phase singular if means plurel as in everyone
2. why is corvées feminine? I would have thought corvés as it is a mix of people (potentially)
And...
In the sentence "Julien s'occupe du tri des déchets"
1. why “tri” and not “trie”, I couldn’t find a “tri” in any tenses?
Merci beaucoup