Вот полный ответ.

(нажми на изображение, чтобы увидеть его полностью)

Ответ:

1. were cycling, started

2. broke, was playing

3. came, was surfing

4. went off, was baking

5. caught, was falling

6. was playing, began

7. was reading, turned on

8. were walking, saw

9. were studying, heard

10. was doing, sat