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Modal verbs

Level: beginner

The modal verbs are: 



We use modals to show if we believe something is certain, possible or impossible:

My keys must be in the car.
It might rain tomorrow.
That can't be Peter's coat. It's too small.

We also use them to do things like talk about ability, ask permission, and make requests and offers:

I can't swim.
May I ask a question?
Could I have some tea, please?
Would you like some help?

Modal verbs




Hello Mosikvd,

Both forms are possible here and there is no difference in meaning in this context.



The LearnEnglish Team

What are the "have to,has to,had to,ought to,be able to ,need,needn't, dare etc are called in grammar? Are they semi-modals?

Hello Noor Muhammad,

The principal modal auxiliary verbs in English are can, could, may, might, must, shall, should, will and would. They are sometimes called full modals as they have all of the characteristics of modal verbs in terms of meaning (expressing modality) and form (they have no inflection, no infinitive form, no participle form, are negated by the addition of 'not' and form questions by inversion rather than with another auxiliary verb).

The verbs you mention, plus others such as had better, are characterised by having some of the elements of full modal but not all of them. Thus, they may express modality but have inflections in the third person present simple, for example (you need > he needs). These are sometimes called semi-modals, quasi-modals or pseudo-modals.



The LearnEnglish Team

Hello! I'd like to seek explanation on the following examples from a book. These pertain to school rules:


Students MAY bring drinks to school, but we CAN'T drink them during classes.

Students CAN'T come to school by motorcycle.

We MUSTN'T use mobile phones during classes.

We CAN work part-time.

We CAN'T get a driver's license.

We CAN have lunch at the school yard.


Students MUST wear their uniform correctly everyday at school.

We MUST wear our indoor shoes.


For the (A) sentences: Is MAY interchangeable with CAN, vice versa? Are CAN'T, MAY NOT, and MUSTN'T also interchangeable? If they are, how can we know which modal verb to use, especially in sentences like these? Does it matter if we use one instead of the other? What implications do they have?

For (B): What should be our basis for using whether "MUST" or "HAVE TO"?

Hoping to hear your feedback.

Thank you so much in advance!

Hello Timmy Ferrer,

I believe that all of your questions about the (A) sentences are answered on the Permission and Suggestions and obligations pages in this section. Please have a look there and if anything is still not clear after that, you are welcome to ask us again.

'you have to do something' means it is necessary to do it or that you are obliged to do it. 'you must do something' has a similar meaning, but it used more often in written rules and instructions (particularly in British English -- this use is less frequent in American English) and is also used to express your opinion about an action. For example, if we are speaking about a new film and I tell you 'You must see it', this doesn't mean you are obliged to see it -- it's a way that I can express my opinion -- in this case in the form of a strong recommendation.

So in the (B) sentences, both 'must' and 'have to' are possible. 'must' would be particularly common in writing, especially in British English, and 'have to' works as well and has the same meaning.

Hope this helps you make sense of it.

All the best,


The LearnEnglish Team

Thank you very much! These make it all clear. :)

Hello. Is the following sentence OK?
- It is necessary not to play in the street.
Does it mean : You must not play in the street.
Thank you.

Hello Ahmed Imam,

In general, yes, it means that. It's slightly awkward to say 'It is necessary not' to do something, though, because it means you should do something, but that something is not doing something.

I'd suggest using your sentence with 'must' or 'You are not allowed to play in the street' instead.

All the best,


The LearnEnglish Team

Hello. Could you please help me?
Are two modals OK?
- By the ages of five, I (could - couldn't) swim 100 metres.
Thank you.

Hello Ahmed Imam,

Only could is possible here. The phrase by the age of suggests a change and an achievement; not being able to swim is simply a continuation and certainly not an achievement.



The LearnEnglish Team



The LearnEnglish Team