Had to + infinitive is generally used to denote an action which was realized in the past as a result of obligation or necessity imposed by circumstances.
| Must is personal We use must when we give our personal feelings
e.g. He is the chief of the company. You must meet him (it is important for you). I must go to the doctor (it is necessary for you). I must write a letter to my parents. I haven't written them for ages. | "Have to" is impersonal We use have to for facts, not for our personal feelings. (You have to do something) because of a rule or the situation:
e.g. The traffic is heavy here. You can't turn right here. You have to turn left (be cause of the traffic rules). Many children have to wear glasses as their eyesight isn't very good. I can't come out with you this evening. I have to work late. | |||
| Compare I must get up early tomorrow. There are a lot of things I want to do. |
I have to get up early tomorrow. I'm going away and my train leaves at 6 o'clock. | |||
Mustn't and don't have to are completely different.
| You mustn't do something. = It is necessary that you do not do it (so, don't do it). You promised to be on time. You mustn't be late. (=You must be on time). | You don't have to do something = You don't need to do it (but you can if you want). He can help me if he wants but he doesn't have to help me (=he doesn't need to help me). |
must, to have to and to be to compared
The verbs must, to have to and to be to have one meaning in common, that of obligation. In the present tense the verbs come very close to each other in their use, though they preserve their specific shades of meaning. Thus must indicates obligation or necessity from the speaker's viewpoint, i.e. it expresses obligation imposed by the speaker.
e.g. I must do it. (I want to do it.) He must do it himself. (I shan't help him.)
To have to expresses obligation or necessity imposed by circumstances.
e.g. What a pity you have to go now. (It's time for you to catch your train.)
He has to do it himself. (He has got no one to help him.)
To be to expresses obligation or necessity resulting from an arrangement.
e.g. We are to wait for them at the entrance. (We have arranged to meet there, so we must wait for them at the appointed place.)
Sometimes the idea of obligation is absent and to be to expresses only a previously arranged plan.
e.g. We are to go to the cinema tonight.
Note. In public notices we find must because they express obligation imposed by some authorities.
e.g. Passengers must cross the railway line by the foot bridge.
The same is true of prohibition expressed in negative sentences.
e.g. Passengers must not walk across the railway line. Visitors must not feed the animals.
In the past tense, however, the difference in the use of the three verbs is quite considerable.
Must has no past tense. It is used in past-time contexts only in reported speech.
e.g. He said he must do it himself.
Had to + infinitive is generally used to denote an action which was realized in the past as a result of obligation or necessity imposed by circumstances.
e.g. I had to sell my car. (It was necessary for me to do it because I needed money.) He had to put on his raincoat. (It was raining hard out side and he would have got wet if he hadn't.)
Was (were) to + infinitive is used to denote an action planned for the future which is viewed from the past. The action was not realized in the past and the question remains open as to whether it is going to take place.
e.g. We were to meet him at the station. (It is not clear from the sentence if the action will take place.)
If the speaker wishes to make it clear at once that the plan was not fulfilled, the perfect infinitive is used to show that.
e.g. We were to have met him at the station. (That means that we failed to meet him.)
However, the simple infinitive may also be used in this case.
In reported speech (in past-time contexts) must remains unchanged in all of its meanings.
e.g. He said he must do it without delay. He said I mustn't tell anyone about it. The doctor told her that she must eat. They believed the story must be true.
Parallel to must, had to + infinitive is also used occasionally in reported speech to express obligation.
e.g. He said he had to make a telephone call at once.
In this case had to is close to must in meaning: it does not include the idea of a realized action but refers to some future moment.
Note. Care should be taken not to replace must by had to in reported speech as the two verbs express different meanings (see above).
Must and May compared
Must and may can be compared in two meanings:
1) Both may and must serve to express supposition but their use is not parallel. May denotes supposition implying uncertainty where as the supposition expressed by must implies strong probability.
Cf. For all I know, he may be an actor. His face seems so familiar. He must be an actor. His voice carries so well. I saw him an hour ago. He may still be in his office now. He always comes at 10 sharp. So he must be in his office now.
2) May and must are used to express prohibition in negative sentences. But may is seldom found in this meaning. In negative answers to questions with may asking for permission we generally find must not or cannot.
e.g. "May I smoke here?" "No, you mustn't (you can't)."
must, should and ought to compared
All the three verbs serve to express obligation. Must, however, sounds more forceful, peremptory.
e.g. You must do it at once. (Вы должны (обязаны) сделать это немедленно.)
Both should and ought to express obligation, advisability, desirability and are used when must would sound too peremptory. (безапелляционно, властно)
е.g. You should do it at once. You ought to do it at once. (Вам следует (нужно) сделать это немедленно.)
Should and ought to are very much alike in meaning and are often interchangeable. In using ought to, however, we lay more stress on the meaning of moral obligation, whereas should is common in instructions and corrections.
e.g. You ought to help him; he is in trouble. You should use the definite article in this sentence.
Notice that ought to cannot be used instead of the emotional should.
Must, ought to and should serve to express supposition implying strong probability. Must, however, seems to be in more frequent use than the other two verbs.
should + Perfect Infinitive, ought to + Perfect Infinitive and was/were to + Perfect Infinitive compared
Should + Perfect infinitive and ought to + Perfect infinitive show that the action has not been carried out though it was desirable;
was/were to + Perfect infinitive indicates an action that has not been carried out though it was planned.
e.g. You should have helped him. You ought to have warned him. (Now he is in trouble)
He was to have arrived last week. (But his plans were upset by some cause or other.)
shouldn't + Perfect Infinitive, oughtn't to + Perfect Infinitive and needn't + Perfect Infinitive с ompared
Shouldn't + Perfect infinitive and oughtn't to + Perfect infinitive show that an action has been carried out though it was undesirable;
needn't + Perfect infinitive indicates that an action has been carried out though it was unnecessary.
e.g. You shouldn't have come (because you are ill).
You oughtn't to have written to them (because your letter upset them).
You needn't have come (because the work is finished).
You needn't have written to them (because I sent them a telegram).
1.Он, должно быть, (вероятно) продал свое пианино. He must have sold his piano.
2. Он, возможно, (может быть) продал свое пианино. He may have sold his piano.
3. Может быть, он и продал свое пианино (хотя едва ли). Не might have sold his piano.
4. Не может быть, что он продал свое пианино. He can't have sold his piano.
5. Ему следовало продать пианино. He should have sold his piano.
6. Ему не следовало продавать пианино. He shouldn't have sold his piano.
7. Он мог и не продавать пианино (не было необходимости). He needn ' t have sold his piano.
8. Ему не понадобилось продавать пианино. He didn't have to sell his piano.
9. Ему пришлось продать пианино: He had to sell his piano.
10. Ему предстояло продать пианино. He was to sell his piano.
1. Они, должно быть, уехали в Нью-Йорк. They must have gone to New York.
2. Они, возможно, уехали в Нью-Йорк.They may have gone to New York. 3. Может быть, они и уехали в Нью-Йорк (хотя едва ли). They might have gone to New York.