Passive voice verb construction

Question

"Hi, "Les étudiants ont été accueillis par le directeur ce matin." Why not:- "Les 
étudiants étaient accueillis par le directeur ce matin." I've been pondering why 
the first is correct but the second verb construction isn't. I realise the 
Kwiziq sentence is presented in a passive voice but it seems to me to be saying 
"they had been welcomes by the director this morning" rather than "were 
welcomes". Any guidance gratefully accepted, Edward"

Answer

Les étudiants ont été accueillis = passé composé, passive voice: "were welcomed"Les étudiants étaient accueillis = imperfect, passive voice.If you want to take this one step further:Les étudiants avaient été accueillis = past perfect, passive voice: "had been welcomed"