Obligation
Fill in: must-have to-should/ought to
9. The buses were all full; I __________________ take a taxi.
10. You ________________________(not take ) my keys, Why did you take them?
11. We ______________________________ be there not later than August, 10.
12. When a tyre is punctured the driver __________________ change the wheel.
13. We _____________________ go there at once.