Ответ:
1. She was washing up yesterday morning.
2. Peggy was writing a story at 7 o'clock last night.
3. They were picking up wood when we came.
4. We were singing songs at 10 o'clock las Monday.
5. I was reading a book when she called.
6. When we came, she was sleeping.
A fox-foxes
A class-classes
A bush-bushes
A lunch-lunches
A potato-potatoes
A box-boxes
A bus-buses