Решение:
- The part of Harry Potter was played by Daniel Radcliffe.
- The kitchen was decorated by my mother.
- These letters were not written by me.
- English is spoken by millions of people.
- Our rivers are polluted by rubbish.
- The washing up is not done by the cook.
- The swimming competition was won by our school.
- Art is not taught by Miss Jones.
- John Lennon was killed by Mark Chapman.
Ответ: 1. was played, 2. was decorated, 3. were not written, 4. is spoken, 5. are polluted, 6. is not done, 7. was won, 8. is not taught, 9. was killed.