3-34. Must

 
Глаголы must и ought выражают долженствование. Глагол must может выражать приказ или очень настоятельный совет. Глагол ought образовался из устаревшей формы прошедшего времени глагола owe в значении «быть должным» и выражает долженствование в сослагательном наклонении (и очень близко по значению к should).

1. Выражение обязанности

1. Глагол must выражает обязанность, долженстование:

We must all keep together (мы должны…).
You must do as you are told.
Soldiers must obey orders without question.
On the other side of the wood there was a field that he must cross.
Plants must get enough light and water if they are to grow properly.
British industry must improve its productivity.
I really must stop smoking.
You must be here before eight o'clock tomorrow.
You really must come and see us soon.

2. Вместо must можно (а в американском английском обычно так и делается) употреблять have (to)/have got (to):

We all have to keep together.
We've all got to keep together.

(have got to более характерно для британского английского)

3. Have to предпочтительнее, чем have got to

3.1. С наречиями частоты – always , never, normally, rarely, sometimes и т.п:

I often have to work at the weekend to get everything done.

3.2. В вопросах и отрицаниях в past simple:

When did you have to give it back? (не ‘When had you got to give it back?’)
We didn't have to wait too long for an answer (не ‘We hadn't got to wait too long...’)

Если have сокращается (I've, he's, it'd), то got выбрасывать нельзя:

The experiment has failed twice before, so it's got to work this time, (not ‘...so it's to work this time’.)

4. Have got не употребляется с will (или любыми другими модальными глаголами):

Employees will have to accept the new conditions or be dismissed. (не ‘Employees will have got to accept... ’)

5. Have to употребляется, когда необходим инфинитив (которого нет у глагола must):

It's annoying to have to get up early on Sundays (не ‘to must get up... ’).

6. Употребление must предполагает, что выражается мнение говорящего, а употребление have to – что необходимость исходит от более объективных обстоятельств (законов и правил, распоряжения руководства и т.п.):

I must do some more work; I want to pass my exam.
In my job I have to work from nine to five. (более естественно, чем ... ‘I must work from nine to five’.)

We must go to New York soon and see your mother.
My wife's an interpreter: she often has to go to New York (более естественно, чем ‘... she must often go to New York’)

I must stop smoking (мое желание)
I've got to stop smoking (врач требует)

This is a terrible party. We really must go home.
This is a lovely party, but we've got to go home because of the baby-sitter.

I've got bad toothache. I must make an appointment with the dentist.
I can't come to work tomorrow morning because I've got to see the dentist.

You really must go to church next Sunday - you haven't been for ages (мое мнение)
Catholics have to go to church on Sundays (этого требует их религия)

Must you wear dirty old jeans all the time? (тебе это нужно?)
Do you have to wear a tie at work? (это правило?)

Это правило почти не соблюдается в США и в американском английском во всех случаях в разговорной речи обычно употребляется have to.

ПРОШЛОЕ

Так как глагол must выражает приказ или совет (которые нельзя выполнить в прошлом), он не употребляется для выражения долженствования в прошлом (за исключением косвенной речи) и вместо него употребляется had to:

She's always had to work hard. (не ‘She's always musted...’)
We had to cut short our holiday because my mother was ill. (не ‘We musted...’)
I had to cycle three miles to school when I was a child.
My parents had to work very hard to build up their business.

Но в косвенной речи можно употреблять как must, так и had to или would have to:

The doctor said that I must stop smoking.
Everybody told me I must stop worrying.
The doctor said that I had to / would have to stop smoking.
Не said they must do as they were told.

БУДУЩЕЕ

1. Глагол must может относиться как к настоящему, так и будущему, но можно подчеркнуть «будущность», употребляя will have to:

We'll all have to keep together.

2. Если уже предприняты какие-то приготовление, то лучше употреблять have (got) to:

When you leave school you 'll have to find a job (это будет только в будущем).
I've got to go for a job interview tomorrow (уже есть договоренность).

Можно употреблять going to have to:

We're going to have to repair that window.

Нужно учитывать, что must звучит очень официально, а will have to делает распоряжение более вежливым:

You can borrow my car, but you must bring it back before ten.
You can borrow my car, but you'll have to bring it back before ten.