Study the following notes and examples

Must and have to both express necessity or obligation. Must is usually stronger than have to and can indicate urgency. On the other hand, must is used to express necessity from the speaker's point of view while have to expresses necessity imposed by circumstances and is rendered into Russian as приходится, вынужден.

I must write to Ann. I haven't written to her for ages. Ann's eyes are not very good. She has to wear

glasses.

In negative sentences to have to denotes absence of necessity. It's my day off so I didn 't have to get up early.

To be to is used to express obligation resulting from an arran­gement. (We are to discuss it next week).

You work too much. You must have a rest. You mustn't smoke here. It's a non-smoking com­partment.

I had to take a taxi to be in time for the appointment. I didn't have to walk. A friend of mine gave me a lift. Did you have to change trains? You don't have to stay late. The work isn 't urgent. We are to sign the contract on Tuesday.

2.3.2. Complete the sentences with the modal verbs must have to or to be to in the correct form.

1. We... leave yet. We've got plenty of time. 2. She seems to be in trouble. We... help her. 3. Our luggage is very heavy. We... take a porter. 4. When you come to London again, you... come and see us. 5. The child hasn't recovered yet. It... stay in bed for another day. 6. They have a lot of work at the office so she... work on Saturdays. 7. You... tell it to anyone. It's a secret. 8. He is very rich so he... earn his living. 9. Come on. We... be late. 10. These old houses... be pulled down in a few months. 11. The conference... open in a few days. 12. You really... make less noise. I'm trying to concentrate. 13. My brother is a milkman. He... get up very early. 14. The doctor says you... take these tablets three times a day. 15. Mother is away so we... look after ourselves. 16. The car broke down so we... walk. 17. Soldiers... disobey a superior officer. 18. How often you... buy petrol for the car? 19.1... speak Italian very much since I came to Rome. Everyone keeps talking to me in English. 20. Your temperature is a little high. You... stay in bed for the next few days. 21. When a fire broke everyone... leave the buil­ding. 22. At present there is disagreement over how child­ren... be taught to be polite. 23. They... announce the winners on April 12^th. It's scheduled. 24. Т simply... have a holiday', said Jean. Т haven't had one for three years'. 25. I'm getting fat. I really... try to lose some weight, like the doctor said.

2.4. MUSTN'T AND NEEDN'T