Modal verb have to (sometimes called a modal construction) is used to express an obligation or necessity (in the affirmative or interrogative form) or the absence of an obligation or necessity (in the negative form). Also verb have to can express confidence, certainty, probability.

Have to is a synonym for modal verb must , and has a connotation of being forced due to some circumstances.

For example:
This answer has to be correct.
This answer there must be, correct. ( Expresses confidence and certainty.)

They had to leave early.
Them had to leave early. ( Expresses obligation, compulsion due to circumstances.)

The soup has to be stirred continuously to prevent burning.
Occasionally soup need to stir so that it does not burn. ( Expresses necessity.)

Using the modal verb have to in the present, past and future tenses

In most cases, the use of modal verbs in the past and future tenses is different from other verbs. The table below shows use of a modal verb have to in different situations.

Remember:
Design don't have to means no need, but not prohibition, while the design must not means a categorical prohibition.

I must answer this letter. (= I have to answer this letter.)
I must answer this letter.

Forms of the modal verb must:

MUST is used in all persons and can refer to the present and future tense.

I must do it now. I have to do this now.
I must do it tomorrow. I have to do this tomorrow.

In the past time must used only in indirect speech.

Negative form: must not (mustn’t).

Interrogative form: must I? etc.

Interrogative-negative form: must I not? (mustn’t I?), etc.

Instead of a verb must verb can be used have to in the present and future tenses, and in the present and past tenses in colloquial form it is used have got to, had got to etc.

In the past tense instead of a verb must verb used have in the past tense followed by an infinitive with to (had to) or had got to.

The interrogative form of the phrase have to is formed using the auxiliary verb to do, and have got to - by placing the verb have before the subject.

The negative form of the phrase have to is formed using the auxiliary verb to do, and have got to - by posing a negation not after the verb have.

There is not much difference in meaning between interrogative forms in present time Have I got to? And Do I have to? etc. no, but the latter is preferable for expression habitual actions. There is no particular difference between the forms of have to in the past tense Had I (got) to? And Did I have to? etc., however the latter is preferable.

Future turnover time have to is formed in the same way as the future simple indefinite tense when using any other verb.

Why does he have to go there? (=Why has he got to go there?)
Why should he go there?

I don't have to go there. (= I haven’t got to go there.)
I don't need to go there.

We didn't have to go there with John.
We didn't have to go there with John.

Did he have to go there with her?
Did he have to go there with her?

Will he have to ask her about it again?
Does he really have to ask her about this again?

I shan’t have to go to that place again.
I won't have to go there again.

Using the verbs must and have to

In the affirmative:

1. Must- to express moral obligation, obligation, imposed by someone or coming from the speaker, as well as internally realized necessity.

You must make your bed yourself.
You must make your own bed.

Go if you must.
Go if you have to (if you think it's necessary).

I must go immediately.
I need to go immediately (since it may be late, etc.).

Have to- to express an obligation, but caused by circumstances.

You will have to make your bed yourself when you join the army.
You'll have to make your own bed when you join the army. ( The army obliges you to do this.)

He has to get up at 7 o'clock.
He must get up at 7 o'clock. ( Circumstances force him - for example, he studies on the first shift.)

Please note:
For the 1st person this difference is less significant.
Have to usually used to express a common action, often repeated, turning into a habit.
Must used to express an extremely necessary, important action.

I have to be at my office at nine every day.
I have to be at work every day at 9 o'clock.

We have to water this cactus twice a month.
We have to water this cactus twice a month.

I must ring him up at 10. It’s very important.
I have to call him at 10 o'clock. It is very important.

2. Must- to express urgent advice or invitation. In such cases it is translated into Russian (necessarily) must, (certainly) must.

You must come and see our new house. It's so lovely.
You should definitely come and see our new house. He is so beautiful.

You must read this article.
You should definitely read this article.

In question form:

1. Must and its equivalents have to And have got to- to express obligation and necessity. At the same time, the equivalents have to and have got to are more common in these meanings in the question than must, since they do not convey additional shades of reluctance, irritation, etc., characteristic of the use of the verb must, which means “necessarily must.”

Must I go there immediately?
Do I have to go there immediately?

When does he have to go there? (When has he got to go there?)
When should he go there?

2. Have to used more often than must to express an obligation in the future, forced from the outside.

Shall I have to answer your question? When will you have to do it?
Do I need to answer your question? When will you need to do this?

3. Have to and (less often) must used to express a common action that is often repeated.

Child: Must I clean my teeth tonight?
Child: Should I brush my teeth tonight?

Do you have to wind your watch every day?
Do you have to wind your watch every day?

In the negative form must not or need not is used.

Must not - indicates that the action is prohibited.
Need not - shows that there is no need to perform an action.

You must not speak like that to your mother.
You shouldn't talk to your mother like that.

You mustn't miss your lectures.
You shouldn't miss lectures.

If you have a headache you need not go to school.
If you have a headache, you shouldn't go to school.

In answers to questions starting with a verb must, used in an affirmative answer must, in the negative - needn't.

Mustn't also has the meaning of a categorical prohibition ( cannot, must not, prohibited), and therefore this form is typical for prohibiting messages to children, expressing warnings in advertisements, etc.

You mustn't go there anyway.
In any case, you can't go there.

Mustn’t is also used to mean “cannot” in a negative answer to the question May...? (Is it possible...?).

May I take that pen? -Can I take that pen? -
No, you mustn't. No you can not.

2. Must used to express an assumption. At the same time, notice the difference in the use of structures

must + Indefinite Infinitive and must + Perfect Infinitive

Must + Indefinite Infinitive used to express probability, assumptions that the speaker believes
quite plausible. This combination translates it should probably be and is used in relation to action in the present tense.

They must know his address.
1. They must (probably) know his address.
2. They must know his address.

Not must be in the library now.
1. He must be in the library now.
2. He should be in the library now.

Must + Perfect Infinitive is used to express a possibility, an assumption of the same nature, but in relation to the past tense, and is also translated as it should probably be.

They must have known his address.
They must have known his address.

They must have forgotten my address.
They must (probably) have forgotten my address.

She must have gone to her parents.
She must have gone to her parents.

Relative pronouns in English language- these are pronouns that form a relative subordinate clause. These include: who, whom, which, whose, that.

The modal verb have to is translated as “ forced, must" Important, that modal verb have to in English is used only when talking about a debt caused by an external reason (if there is a compulsion to perform an action).

Let me explain with an example what debt caused by an external reason means. Take a look at two Russian sentences:

I must help your parents.
I must be at work by 10 o'clock.

In both sentences we use the same Russian verb must. But in the first sentence you say “I must...” because you feel a sense of duty (an internal need). And in the second sentence there are external circumstances that force you to arrive at work by 10 o'clock (angry boss, fines for being late, etc.).

These sentences will be translated into English differently. When you talk about an internal need, use the modal verb must (more on this later). And when we're talking about about a duty that has external reasons (I owe it because someone or something forces/forces/obliges me to perform an action), then in such cases feel free to use the modal verb have to.

Modal verb to have to. How to use it correctly?

Sentences with the verb have to are constructed according to the following scheme:

Subject + have to + any verb from the dictionary + everything else.

That is, you put the infinitive of the main verb immediately after have to and get a sentence with the meaning of obligation or need to do something. For example:

I have to work.
I have to work.

You have to drink 2 liters of water every day.
You should drink two liters of water every day.

How do have to change according to tenses and persons?

The answer to this question is very simple - just like the verb have without the particle to. In the third person singular we have the form has to, in all other cases - have to:

In the past time - had, in future - will have. Examples of sentences with the modal verb have to in different tenses:

Differences between modal verbs have to and must.

The meanings of these modal verbs are very close. Therefore, if you are just starting to learn English, then you don’t have to worry about it and always use the modal verb have to instead of must.

But there is still a subtle difference in the meanings of these verbs: must denotes a necessity or obligation caused by the personal opinion of the speaker, and have to denotes a necessity caused by external circumstances.

Interrogative and negative sentences with have to.

The modal verb have to in interrogative and negative sentences requires the presence of an auxiliary verb do. This is how it differs from other modal verbs - when constructing interrogative and negative sentences, it behaves like a regular (non-modal) verb. For example:

You have to work.
You have to work.

You don't have to work.
You don't have to work.

Do you have to work?
You have to work?

Place the to particle in the correct place.

Eat a big difference between the verb to have and the verb have to. Compare:

I have something to do today.
I have something to do today. (literally: “I have something to do today”)

I have to do something today.
I have to do something today.

In the first case, have is a regular verb, translated as have. By the way, the verb have is very common in English and can be both semantic and auxiliary.

In the second case, we have a modal verb have to, which you already know a lot about. So don't forget about the to particle - it's very important.

Turnover have to (same as verb must) in English has the meaning “to be due, obligated.” Often actions in it are forced, since they do not depend on the person and are caused by external reasons.

Table: Turnover have to

I won't be at work tomorrow. I have to go to the doctor. I won't be at work tomorrow. I have to go to the doctor.
Linda has to get up early. She works very hard. Linda has to get up early. She works a lot.
You have to do an exam at the end of course. You must take an exam at the end of the course.

In the past tense the construction takes the form had to:

I wasn’t at work yesterday. I had to go to the doctor. I wasn't at work yesterday. I had to go to the doctor.
We went to the store last night. We had to buy some food. We went to the store last night. We had to buy some food.

2

In interrogative and negative sentences, the do form of the verb is added to have to. The rules here are the same as in Present Simple and Past Simple.

Table: Have to and past tense

What time do you have to leave? When should you leave?
Does Jane have to work on Saturdays? Does Jane have to work on Saturdays?
How much did you have to pay for the new house? How much did you have to pay for your new home?
I’m not going anywhere tomorrow, so I don’t have to get up early. I'm not going anywhere tomorrow, so I don't have to get up early.
Ian doesn't have to meet me. I know the way. Ian shouldn't meet me. I know the way.
Dan didn't have to wait very long. The bus arrived soon. Dan didn't have to wait very long. The bus arrived soon.

3

Both forms can be used when expressing a personal opinion about what should be done:

If there is a statement of fact, and not a personal opinion, have to is used exclusively.

Jane won't be at work today. She has to go to the doctor. Jane won't be at work today. She should go to the doctor.
In many countries, men have to do military service. In many countries, men are required to serve in the military.

Consider the modal verb have to / have got to in English, its usage and tense forms with examples and translation.

Modal verb Have to and its meaning

People who are not native speakers have a difficult situation with this branch of grammar; in fact, modal verbs sometimes mean the same thing.

For example,

Have to or Must?

Must(should) is based on personal requests, and the modal verb have to(obliged) due to circumstances from outside and represents the lack of an alternative when asked. Let's look at an example:

🔊 You must go on a budget. - You must go to the budget.
(your family, in principle, will be able to afford your paid education, but they would like to protect themselves from such expenses, you should have a choice)

🔊 You have to go on a budget. - You must go to the budget.
(you have no choice, your family won't be able to pay your education, so you have to (obliged) to try)

Important Features Have to

Important! Distinctive features modal verbs have to And have got to are: the self-sufficiency of these verbs (they can express the category of person and number) and, unlike other modal English verbs, a particle is used before the main verb after them to.

To have and have to should not be confused

Verb to have is translated “to have / own”, and the modal verb have to- “obliged / must”. Below are examples of sentences.

🔊 I have a phone. - I have a phone.

🔊 I have to go.- I have to go.

Absolutely different meanings, is not it?

Have to forms

Comment! Interrogative and negative forms of the modal verb have to formed together with an auxiliary verb to do(See example sentences below the summary table).

Present Simple:
a) Statement
🔊 She has to come to the office at the right time. - She must come to the office at the right time.
b) Denial
🔊 I graduated from school and I don't have to do my homework anymore. - I graduated from school and I'm more is not obliged to to do homework.
c) Question
🔊 Does she have to do this project? — Should will she do this project?

Past Simple:
a) Statement
🔊 I had to write to him. - I should have write him.
b) Denial
🔊 I didn't have to ask her about her age. - I shouldn't have ask her about her age.
c) Question
🔊 Did I have to help you? - I should have can I help you?

Future Simple:
a) Statement
🔊 Jane will have to go at 7 PM. — Jane have to go at 7 pm.
b) Denial
🔊 Isabella won't have to write this work. — Isabella you won't have to write this work.
c) Question
🔊 Will I have to do this exercise? - To me have to do this exercise?

What is the difference between Have got to and Have to?

In addition to tense forms, the modal verb have to there is a form have got to(she met above). The difference between these forms is practically not noticeable. So, have got to used in British English mainly only in the present tense and indicates a specific, non-repeating action.

The modal verb Have to is used:

• when we are forced (not obliged) to do something due to external circumstances (not of our own free will);