1) came, has
2) returned, listened
3)entered, drew
4) came in, did
5) aired, catched
6) met, went
7) washed, knocked
1. When my father came home, I was having dinner.
2. When Alice returned, I was listening to the radio.
3. When mother entered his room, he was drawing a picture.
4. When my sister came in, I was doing my lessons.
5. When her aunt was airing the room, she caught cold.
6. When I met her, she was going to the office.
7. He was washing his face when somebody knocked at the door.