Bonjour,
Réponse :
1. Harry wasn't watching TV at 8 pm last night. He was studying..
2. Jill was wearing her uniform at work yesterday.
3. She was listening to her teacher when he asked a question.
4. Anna was eating when he arrived.
5. Greg was studying when we went to his place.
6. They were having a good time at the party, so they decided to go home.
Explications :
Prétérit be + BV-ing : (+ ) was / were + BV-ing
( - ) wasn't / weren't + BV-ing