3. Jennifer hasn't finished her homework.

4. They have met the president.

5. No, we haven't.

6. Has Roberto visited Vancouver?

7. Yes, he has.

8. Mrs. Smith hasn't read the book.

9. He has been a teacher.

10. Have you been in jail?

11. I haven't cleaned my room.

12. No, they haven't.

13. Has she been sick?

14. Has he swum in the ocean?

15. They haven't arrived.

16. Where have they been?

17. We have lived here for a year.

18. What has he done?

19. It hasn't rained for a long time.

20. Who has finished the homework?