Compléter Conditional Clauses. 3.Version en ligne Fill in the blanks with the correct MODAL VERB. par Isabel Gallego Chaves 1 have to must shouldn't can has may cannot to should could mustn't 1 . If computers didn ? t have a firewall installed , hackers get into your system . 2 . If she doesn't want to miss her bus , she hurry . 3 . If Robert doesn't arrive soon , I leave without him 4 . Cardboard and paper be recycled if you put them into the correct container . 5 . If you have an accident , you signal the place with reflecting triangles . 6 . If your mark is under 50% , you pass the test . 7 . If you don ? t want to sunburn , you wear some sun lotion . 8 . In Spain if you drive over the speed limit , you go to prison . 9 . If you want my advice , you pay attention to Sarah ? s comments . 10 . You tell lies to the police if they question you about a crime .