Bonjour
a- I was watching the news when you rang.
b- They were gardening when they suddenly heard an explosion.
c- Just as I was opening the door, The dog escaped.
d- While we were fishing, Emerik fell in the river.
preterit simple = pour une action passé soudaine , terminée.
preterit be -ing (preterit progressif) = pour une action passée qui était en cours, en train de se produire ...
bonne journée ☺☺☺
