Answer:
1. Someone should send the email today.
2. The employees have left the documents behind.
3. They served the breakfast in the dining room.
4. Has anyone read the instruction?
5. Someone offered him a good job.
6. Someone had to call the ambulance.
7. The mechanics will repair my car next week.
8. Someone is breaking down the old bridge at this moment.
9. They said he is an excellent guitarist.
10. Open the windows.
11. My parents adviced me to get a visa.
12. Why did someone break the glass?
Explanation:
I used "someone" when the doer wasn't identified, I think you're free to use "you" or "them" depending on the situation.
