What are “Must and “Have”?

Must and have to are both verbs in English, but they are used differently. We use must when talking about something certain and subjective, whereas have to is used to talk about obligation that is objective.

When to Use Must:

We use the modal verb must when we want to express personal obligations or express what the speaker think is necessary. Overall, the modal verb must is related to obligations that are subjective to us.

  • I must stop smoking.
  • You must visit us soon.
  • He must work harder.

How to Use the Modal Verb Must:

Must is a modal auxiliary verb. It is always followed by the main verb, and this is how it structured:

Subject + must + main verb (without “to”).

Let’s look at some examples:

SubjectAuxiliary mustMain verbRest of the sentence

As the examples shows the main verb is only the base verb without “to”.

🚫 Incorrect: I must to go home.

✅ Correct: I must go home.

When to Use “Have To”:

We often use have to express impersonal obligations, things that often related to others or on oneself. Therefore, have to is often objective rather than subjective.

  • I have to walk the dog.
  • In London you have to drive on the left.
  • Salama has to be at work on time.
  • Children have to go to school.

As we can see from the examples, the obligation is not subjective rather the obligation is imposed from the outside, objective.

How to use “have to”:

It is worth to clarify that “have to” is not a modal verb in fact it is not even an auxiliary verb. It comes to serve as substitute for “must”, because it is enabling people to express the idea of obligation or duty.

The structure of “have to” is:

Subject + auxiliary + have + infinitive (with to).

Let’s see some examples:

FormSubjectAuxiliary verbMain verb “Have”Infinitive (with to)Rest of the sentence
AffirmativeShehasto work
NegativeIdo nothaveto seethe doctor
Questiondidyouhaveto goto school
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