Must and Have to for intermediate learners

'Have to' and 'must' have the same meaning and are used to express obligations. However, they are used in different situations and are not interchangeable.

"Must and Have to" in English Grammar

What Are Must and Have to?

'Must' and 'have to' are two common modal verbs in English that are used to indicate that something is necessary or required. Both of these verbs are used in English, but 'have to' is generally more common among American English speakers.


Just like the other modal verbs in English, we use this pair with the base form of the verbs. Look at the following examples:

She must stop this mess at once.

We must go to the book store and change it.

I have to leave you for good.

Do not forget to use 'to' in this modal verb.


Unlike most modal verbs which have a single form for all persons, the form of 'have to' changes when used with a third-person singular subject.

She has to learn German if she wants to travel to Germany.

These two modal verbs are also used in negative statements and questions.

To form negatives with 'must', simply add 'not' after it. The contracted form is 'mustn't'. For example:

I must not talk to her like that.

To form questions, move 'must' to the beginning of the sentence, before the subject. Pay attention to the examples below:

Must I study that hard?

We can also use 'must' in question tags. Look:

They must write their proposals, mustn't they?

Your friend must come with you, mustn't he?


Please note that mustn't is only used in informal conversations and never in formal, written English.

To form questions with 'have to', you need an auxiliary verb. The subject and auxiliary verb are then inverted and 'have to' follows the subject. Pay attention to the example:

Do I have to eat lunch at this hour?

Here, 'do' is added as an auxiliary verb to form a question.

To form negative sentences with 'have to', you can add 'not' after the auxiliary verb 'do/does'. For example:

I don't have to surrender to you sir.


As mentioned above, 'must' and 'have to' are used in various contexts and situations. They can be used to:

  • Indicate rules
  • Suggest and recommend something
  • Express something likely or logical

Indicating Rules

'Must' and 'have to' are both used to express a necessity or requirement, and to indicate that something is required to be done. Look at the following examples:

She must stop running from her problems.

I have to complete my novel this week.

Suggesting and Recommending Something

'Must' and 'have to' can also be used to give suggestions or advice. When used in this way, they usually imply a strong recommendation. Study the following examples carefully:

Don't you think you have to try the shoes on first?

I think they must avoid all this drama.

Expressing Something Likely or Logical

If we want to talk about a future event or something that is likely to happen, we can use 'must' and 'have to' as modal verbs. In this context, they can be used to express a high degree of probability or certainty. Look at the examples below:

Camping must be a fun activity.

It has to be her then.


'Have to' is also used to show a sense of annoyance or frustration toward someone or something. Pay attention to the following examples:

Does she really have to be that loud?

It had to start snowing the moment we stepped into the jungle.


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