1. these books (return) to the library yesterday. 2. the books must (return) to the library till the end of this month. 3. why your home task (not do)? 4. the patient was taken to the hospital today, and (operate) tomorrow morning. 5. this room (use) only on special occasions. 6. litter must not (leave) here. 7. the children (take) to the circus this afternoon. 8. dictionaries may not (use) at the examination. 9. usually this street (sweep) every day, but it (not sweep) yesterday. 10. this book (leave) in the classroom yesterday; it (find) by me. 11. thousands of new houses (build) every year. 12. this room (not use) for a long time.