1)We were leaving the party when he arrived.

2)What were they doing when you saw them?

3)When he came to see me, I was having a bath.

4)I was reading a book when I heard the noise.

5)They were having supper when he visited them.

6)We were sitting here yesterday when he passed.

7)She was crossing the road when she saw the accident.

8)I was choosing the present when my friend entered the shop.

9)When my aunt was going home, she lost her purse.

10)His brother was sleeping when he left.