IV. Sign

1. B. you can't smoke here

2. B. No food

3. A. Motorbike isn't allowed to ride

4. D. Wash your hand

Word form

1. scared

2. worried

3. helpful

4. toothache

5. regularly

6. clothes

7. appointment

8. yourself

9. different

10. touching 

11. carefully

12. unhealthy

13. serious

14. kindly

15. children

15. Children should spend less time on video games.

16. You ought to keep the house clean and tidy.

17. It usually takes Mr. Johnson 15 minutes to walk to work.

18. It takes Mary two hours every week to study in the library.

19. I often spend 10 minutes walking from my house to school.

20. Does that work take you half an hour to do.

21. We spent half an hour getting to the airport.

22. It will take her a long time to recover from the illness.

23. Are you interested in playing soccer after school.

24. My students are always going to school early

25. She always goes to work early.

26. Will you please take care of the house while we are away?

27. Kate should revise her lesson before the test

28. It isn't necessary for you to go to school early.

29. It is necessary for Hoa to water that tree everyday

30. You didn't have to finish the test by Saturday.