PART FOUR - GRAMMAR (7 marks) Complete the sentences with the correct modal verbs from the box. could can't have to don't have to should shouldn't mustn't 17. ADNOC station staff wear uniforms so the customers can identify them. 18. When we use the auto lock, we lock the car door manually. 19. We say this product is handmade. It isn't! That's illegal. 20.1 leave my house at 6:30. I am on the schedule to start at 7:00 21. This material looks strong. Let's test it to see if it break. 22. We have a small problem with the design, but it be too difficult to solve if we all work together. 23. Employees leave work without telling the manager. It's the rule! 17