1) I was listening to records in my room so I didn't hear the bell. (to listen to music = écouter de la musique ; to listen to records = écouter des disques; pas la peine de rajouter music)
2) Whe we saw our neighbour, she was watering (elle était en train de..) flowers.
3) We were having breakfast (en train de..) when the postman arrived. (+ ou - on était en train de prendre le petit dej' qd le facteur 'arriva' )
 4) It was raining so we stayed in and played cards
5) Nelly was sitting on the beach and her brothers were swiming
6) He didn't see us because he was sleeping on the sofa (comme tu as mis)
7) Was he repairing his car when you called him?
8)Just as she opened the cupboard (action immédiate car il y a 'just' devant), the bread falled out(action immédiate)
9) When Dad heard some shots, he was writing a letter 
10)Where were you going when you met them (tu as mis meeting : tu ne mets le verbe en ind que qd c'est 'aux + verbe'= BE +ing
11)She knew (elle savait pas elle était en train de savoir donc prétérit)the answer but she didn't want to tell her neighbour 
12)Was  your husband shaving while you were brushing your teeth?
Ne mets jamais le verbe en ING tout seul; il faut qu'il y ait un auxilliaire dexant.
J'espère que j'ai pas trop fait de ftes et que mes petites explications pourront t'aider
Good luck

ça t'a aidé où pas???? No news, good news!!!!!