Circle the correct answer to complete the sentences.
1. These books ............ (must returned/ must be returned) to the library tomorrow.
2. Mr.Nam ............ (tought/ was tought) us English last year.
3. More than 100 houses ............ (build/ were build) in this area last month.
4. Our teeth ............ (should brush/ should be brushed) twice a day.
5. He ......... (wrote/ was written) that letter two days ago.
6. No one ......... (has made/ has been made) mistakes.
7. These cars ............ (make/ are made) in Japan.
8. Their photos ............. (took/ were taken) by a professional photographer.