building blocksModals of Necessity: Must, Have got to, Have to


These three verbs are modal verbs.

Modal verbs are helping/auxiliary verbs that express ideas like ability, necessity, and prohibition. Many modal verbs have more than one meaning. They are always followed by the simple form of a verb. For example:

Andrew has to pay his rent every month.

This shows that Andrew has no choice. He has an obligation to pay his rent. He will be in trouble if he does not pay his rent.

Modals of Necessity

Let's read about how to express necessity or obligation. The modal verbs “must,” “have to” and “have got to” show that something is not optional; it is necessary.

Must is the strongest and most serious modal verb of the three and is most common in writing. It is unusual to use “must” in questions.

I must study tonight.

Have got to is most common in informal speech. It is not used in questions.

I have got to study tonight. = I must study tonight.

Have to is the most commonly used modal of obligation. It is useful for forming questions and negatives.

Be careful! The subject and verb must agree for he/she/it subjects AND the question form requires “Do/Does/Did”.

Example Question Answer
I have to study tonight. Do I have to study tonight? Yes, I do.
She has to study tonight. Does she have to study tonight? No, she doesn't.

Remember: “have got to” and “have to” are modal verbs and require a simple verb to follow them. The “to” is part of the modal; it is not an infinitive “to”.

There is only one way to express past time with these modal verbs: HAD TO. (There is no past tense of must/have got to.)

For example:

Present Time Past Time
We must show our passport at the airport. Last night, we had to show our passport at the airport.
I have got to pay my phone bill soon. I had to pay my phone bill this morning.
They have to go to the meeting today. They had to go to the meeting yesterday.

Pronunciation notes:

The modal verb have got to is often contracted as: I've got to and sounds like “I've gotta...”

The modal verb have to often sounds like: “I hafta...” or “She hasta...”

gotta”, “hafta”, and “hasta” cannot be used in written English. They are only used in speaking.

When you are sure that you understand the lesson, you can continue with the exercises.