Ответ:
1. Tom was told to stop talking (by the teacher).
2. A new comercial center in town is going to be opened (by them).
3. Our homework have been done (by us).
4. The building was destroyed (by the fire).
5. The offer won't be accepted (by them).
6. She was disappointed by his behavior.
7. The next Olympics is going to be hold in London.
8. A beautiful landspace can be seen from my window.
9. She must be told about the meeting.
10. Our products are advertised in the newspaper.
11. A letter is being written by Helen.
12. The plants are watered (by my aunt) every night.