1. He was watching a new film while his small brother was sleeping in his room. (Continuous, из-за while, который указывает на процесс какого-нибудь действия).
2. When Jack saw Bobby, he was talking with his friends. (Действие, которое было в процессе (continuous), прервалось другим одним действием (simple))
3. My mother was washing up at 7 o'clock yesterday. (Есть четкое время - 7 часов, но не указана продолжительность)
4. I was reading the book when Tom called me. (=2)
5. It was raining while I was writing my report (=1)