MUST
The modal verb must has the following meanings:
1) Obligation from the speaker’s point of view. Inthis meaning it is found in affirmative and interrogative sentences and followed only by the simple infinitive.
You must come to class on time.
We also use must to express obligation imposed by authorities in orders and rules.
Safety helmets must be worn.
All visitors must sign in.
Must is found in present-time contexts with reference to the present or future:
He must go there tonight.
In past-time contexts must is used only in reported speech, i.e. the rules of the sequence of tenses are not observed with it.
He said that he must go there.
In order to express obligation referred to the past had to is used instead of must:
I had to go there.
2) Prohibition:
He must not leave his room for awhile.
This meaning is expressed in negative sentences and must is also followed by the simple infinitive.
Note 1. Absence of necessity is expressed by other verbs (see to have and need).
3) Emphatic advice, which is usually rendered into Russian by means of “ непременно, обязательнодолжны ”:
We must have a party at the end of term.
You must come and see us when you're in London.
You must stop worrying about your son.
You mustn't give another thought to what he said.
You mustn't miss the film. It is very good.
This meaning is found in affirmative and negative sentences and is closely connected with the two above mentioned meanings.
4) in its suppositional meaning must expresses supposition implying strong probability:
Look at that car! Ali’s parents must have a lot of money!
It must be late as the streets are deserted.
Must in this meaning is found in affirmative sentences.
In Russianthis meaning is generally rendered by means of the attitudinal adverbs «(вполне) возможно», «вероятно», «наверное», «наверняка».
In English this meaning may also be expressed by means of the attitudinal adverbs probably, evidently, obviously, apparently.
In themeaning of supposition implying strong probability must may be followed by different forms of the infinitive.
a) If reference is made to the present, the Simple Infinitive is used with stative verbs.
He must know her. They went to the same school.
b) With dynamic verbs must is used in combination with The Continuous Infinitive to express strong probability referred to the present.
The book is not on the shelf. Jane must be reading it.
Let's have something to eat. You must be starving.
Listen. It must be raining outside.
Note 2. If must is followed by the simple infinitive of dynamic verbs, it expresses obligation.
Jane must read the book. You must stay here.
c) Must in combination with the Perfect Infinitive refers the action to the past.
Someone must have taken the key because it isn’t there.
We realized he must have lied.
d) Must with the Perfect Continuous Infinitive is used to indicate an action begun in the past and continued into the moment of speaking, or an action of some duration in the past.
He must have been waiting for an hour.
Note 3.Must is not used to expresssupposition implying strong probability in negative sentences and with reference to the future. In this case the attitudinal adverbs probably, evidently, obviously, apparently or the phrases be bound to be likely to (to refer the action to the future) are used instead of must.
It will probably rain tomorrow.
It's bound to raintomorrow.
Exercise 52.Choose the correct option
1. His German is very poor. He must (study/be studying/have studied) very hard.
2. His German is very good, he must (study/be studying/have studied) very hard.
3. His German is considerably improved, he must (study/be studying/have studied) hard during his holiday.
4. He must (study/be studying/have been studying) German these two years, his German is rather rich and fluent.
5. She must (have taken/be taking/have been taking/ a bath at that moment, that's why she did not answer your call.
6. She must (be/be being/ have been) at home now, we saw her leaving the office.
7. She must (be/be being/have been) at home, she can't go away because there is no one to look after her sick mother.
8. You must always (think/be thinking/have thought) twice before you say anything.
9. Now he must (think/ be thinking/have thought) of what she has said.
10. He knows they are coming. They must (write/be writing/ have written) to him of their arrival in due time.
11. She must (play/be playing/have been playing) the piano now.
12. The foreigner must (understand/understood/have understood) me, for he nodded his head.
13. Where is Sara? I haven't seen her for a long time. — She must (stay/be staying/have stayed) at her friends'. She wanted to spend July with them.
14. He must (get/be getting/ have got) all he needed, otherwise he would have come again.
15. We must (meet/have met/have been meeting) somewhere before.
Exercise54.Open the brackets and use the proper infinitive after the verb must
1. Look! All people in the street are going with their umbrellas up. It must......... (rain).
2. He has changed his job. He must......... (follow) your advice.
3. He must......... (fall) ill. Otherwise he would have come to the party.
4. Where is Michael? He must......... (be) here by now. — He lives in the country. He must......... (miss) the train.
5. What a dreadful noise! What is the matter? — Our neighbors must......... (quarrel) again.
6. Nobody must......... (notice) that he was not used to speaking in public.
7. The criminal must......... (be) very careful. He did not leave any fingerprints.
8. We are late, I am afraid. Ann must......... (wait) for us.
9. He must......... (forget) that he promised to come.
10. They must......... (write) a composition for two hours. They must......... (be) tired.
11. You must......... (misunderstand) me, I did not want to hurt your feelings.
12. Nobody must......... (see) him enter. Everybody startled when he came in.
13.I hear someone's steps outside. She must......... (go).
14. You may find him in the garden. He must......... (read).
15. It is impossible to change anything. One must......... (take) things as they are.
Exercise55. Paraphrase the following sentences using the verb must
Example: I am sure they have changed the time. — They must have changed the time.
1. They are in Greece. I am sure they are enjoying themselves.
2. She is an experienced teacher. I am certain she has been working at school for at least twenty years. 3. They have probably finished painting the house.
4. I feel sure she is at home.
5. Probably they have already passed the frontier.
6. She is sure he is playing cards with his friends.
7. She is not very young, as she seems to be. I think she is nearly forty.
8. I think you have visited this place before.
9. He has to do a very urgent task. I feel sure he is working now.
10. He is so absent-minded. I am sure he left the letter unanswered.
11. You know he is a good tennis player. He is no doubt has won this match.
12.I won’t bother you any longer; no doubt you feel tired of my talking after a tiring day.
13. It is clear that they are expecting somebody.
14. She was obviously upset by something; I never saw her so nervous.
15. The youth is probably reading something funny. He is smiling all the time.