Question

Exercise 18. Fill in the blanks with mustn't or ought not to:
1. You .............. take any medicine without the doctor's advice.
2. You .............. keep these library books with you for more than a week.
3. We .......... leave the car unlocked.​

Answer 1

1) you mustn't take any medicine without the doctor's advice
2) you mustn't keep the library books with you for more than a week
3) we mustn't leave the car uncloked