Answer:
1. The room wasn't cleaned by him yesterday.
2. A letter shall be sent to my friend by me next Monday.
3.This book was written by whom?
4. The text was being discussed by us when he entered.
5. The topic of the discussion has already been chosen by them.
6. When was this information received?
7. His pet must be fed everyday.
8. My grandfather's house was built by him two years ago.
Explanation:
