Modal Verbs


We normally use verbs in order to describe actions. Yet sometimes, one verb is not enough. Sometimes we need two verbs to convey a more accurate meaning. One of the main ways to do this is by using modal verbs.

Modal verbs, also known as modals, define the degree of possibility, certainty, necessity, etc. of a certain action. Thus, they will typically appear before another verb in a sentence. The most common modal verbs are: can, may, must, shall, could, might, should. and shall.


I can walk to your house.

The doctor might ask you a few questions.

You must listen to this song!

I couldn’t care less…

They wouldn’t tell me their secret


Modal verbs are one of the main ways in the English language to express modality. In language, modality is a category that includes everything that articulates the relation between a certain action or fact and reality – meaning, its possibility, probability, necessity, obligation, etc. In other words, modality can relate to one’s knowledge, on one hand, and about one’s will on the other hand. Roughly speaking, modal verbs belong to those two categories: for example, the modal verb may typically refers to what someone knows about reality while the verb should typically refers to what someone believes necessary.


This may be the house we saw earlier. (possibility)

You shouldn’t run with scissors. (prohibition)

However, it should be noted that the same modal verbs sometimes have a different meaning, depending on the context. See, for example, how the same verbs we used earlier can have a completely different meaning:


You may enter my office now (permission)

Twenty kilos should be enough (assumption/deduction)

The verb must, for instance, is commonly used both for expressing obligation as well as certainty:


My parents must be home by now. (meaning: I am sure my parents are home)

You must take care of your pets. (meaning: It is important/vital/necessary that you take care of your pets)

The verb will

Interestingly, one of the most common modal verbs isn’t normally thought of as one: the verb will, with which we form the future tense. But indeed, from a grammatical point of view, will behaves exactly as a modal verb. Actually, it was used originally to express one’s will, and became the standard way to form the future.


Modal verbs are joined with semantic verbs to create a larger verbal structure. In terms of grammar, in this structure the modal verb acts as the main verb, but it is the other verb that carries all the semantic content, that is, the meaning of the verb phrase. Because of this, the modal verb is considered an auxiliary verb, and the other, semantic verb is the main verb.

Of course, there are other verbal structures that include more than one verb. What distinguishes modal verbs, then, is that they do not inflect, i.e. they do not change according to the person and number of the subject, but rather always keep the same form.



She can tell the time by looking at the sky.

This must be the place.

She cans tell the time buy looking at the sky.

This musts be the place.

Furthermore, unlike other verbal forms, the conjunction “to” is never to be found between the modal verb and the main verb.


They should see the place before signing a contract.

They should to see the place before signing a contract.

An exception to this rule is the verbal form ought to, which is sometimes seen as a modal verb.


She ought to drink more water.

Another verbal form that behaves similarly are perfect tense verbs. Yet while the main verb in a perfect tense clause is a past participle (V3), the main verb in a modal clause is an infinitive, i.e. the bare form of the verb:


I could see it happening

I could seen it happening

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