I was in serious doubt about this: maman a envoyée, but here it seems the verb take the plural from les cadeaux?
Exactly! When the Complément d'Objet Direct (Direct object) comes before the verb and the auxiliary verb is avoir, the Participe passé (Past participle) agrees in gender and number with the object.
Yes, when the direct object comes before avoir, then the participle has to agree in gender and number. "Que" is the clue there, and it also happens frequently with questions and the personal pronouns le/la/les.
Why can't I replace "ce sont" with "voila" in this sentence ?
"Ce sont" = these are
"Voilà" = there is/are (or alternately "here is/are")
Why is "ce sont" correct but "elles sont" incorrect?? Elles=they; no?
Agh!! I hate that in my life I always call her mother and never mum, so I tend to translate it always as mère.