giúp e vs e cảm ơn ạ

IV. Complete the sentences with the correct form of must, have to or should. Use the information in brackets to help you.

1. Phong... write three one-thousand-word essays for his course. (It's necessary.)

2. We. tidy up the house. Mum will be home soon. (It's a good idea.)

3. You. park here. You'll get a fine. (obligation not to do this)

4. You pay for children. They can come in for free. (It isn't necessary.)

5. The sign says you. keep your dog on a lead. (It's necessary.)

6. You. smoke anywhere in the building. It isn't allowed. (obligation not to do this)

7. You. wear a helmet when you ride your motorbike. It's the law. (It's necessary.)

8. Do children go to school on Saturdays? (Is it necessary?)

9. You. wear jeans to a job interview. (It isn't a good idea.)

10. You. pay for the coffee. It's free. (It isn't necessary.)