French language Q&A Forum

I am wondering why in a lesson of monter dans and descendre de that a quiz question is using débarque?  Thanks.  (Rose débarque du bateau" means:)

The passive voice in several examples where we needed "was sent" and "had prepared" used plus que parfait ie) était envoyé and avait préparé, but for "the students were welcomed", my use of étaient accueillis was incorrect and the correct answer was the p.c.: Les étudiants ont été accueillis was correct. This seems illogical to me. Please explain the difference.

Is the l' before on something Kwizig students have studied up to or including B2? If yes please cite the lesson.

If not yet studied, please provide a grammar explanation. Thank you.