Modal Verbs

1. What is a Modal Verb?

A modal verb is an auxiliary verb that expresses necessity or possibility. An auxiliary verb, also called a helping verb, “helps” other verbs show moods and tenses. Auxiliary verbs include forms of do, be, and have.

The most common modal verbs include must, shall, will, should, would, can, could, may, and might.

Modal verbs are different from other verbs in a few ways:

You don’t add an “s” to form the third-person present tense. You wouldn’t say he cans, she cans, etc.
They also don’t have infinitive forms. I’m canning, I’m woulding, etc. would not be correct.
Modal verbs are followed by a base verb (the plain, dictionary definition of a verb, like jump, help, sing, play, or read).

2. Examples of Modal Verbs

Example 1

You should stop biting your fingernails.

This example uses the modal verb “should.”
“Should” is used to express advice about biting fingernails.
The base verb “stop” follows the modal verb “should.”

Example 2

You must take out the trash before dinner.

The modal verb “must” is included in this sentence.
In this example, “must” is used to express a necessity or obligation.
The modal verb “must” is followed by the base verb “take.”

Example 3

Joey might play soccer instead of basketball next year.

This sentence uses the modal verb “might.”
“Might” is used to express possibility in this example.
The modal verb “might” is followed by the base verb “play.”

3. Types of Modal Verb

Let’s look at some of the different ways you can use modal verbs:

a. Probability

Modal verbs can be used to show how likely something is, or to express probability.

Example 1:

If she’s not at home, she must be at school.

This sentence uses the modal verb “must.”
“Must” shows probability because it suggests that the person in the sentence is very likely to be at school.
Modal verbs need to be followed by a base verb. In this case, the base verb is “be.”

Example 2:

It might rain later today.

This example uses the modal verb “might.”
“Might” shows that there is a possibility that it will rain later today.
The base verb “rain” follows the modal verb “might” in this sentence.

Example 3:

That can’t be true!

In this example, we see the modal verb “can” (or, in this case, “can’t).
This use of “can’t” shows that there is no possibility that something is true.
The modal verb “can’t” is followed by the base verb “be.”

The modal verbs “will” and “would” can also express probability.

Example 1:

I will go to soccer practice after school today.

This example includes the modal verb “will.”
“Will” is followed by the base verb “go.”
In this example, “will” is used to demonstrate that it is very likely or certain that the speaker will go to soccer practice after school.

Example 2:

I would go to soccer practice after school today if I find a ride.

In this sentence, we see the modal verb “would.”
“Would” is followed by the base verb “go.”
In this case, “would” is used to express the probability that the speaker will go to soccer practice. It is not likely that the speaker will attend practice unless he or she can find a ride.

b. Ability

We can use the modal verbs “can” and “could” to describe ability.

Example 1:

Brittany can run eight miles without stopping.

This sentence uses the modal verb “can.”
In the example, “can” demonstrates Brittany’s ability to run eight miles.
“Can” is followed by the base verb “run.”

Example 2:

My grandmother could sew beautiful dresses.

The modal verb “could” is used in this example.
“Could” describes the grandmother’s ability to sew dresses.
The modal verb “could” is followed by the base verb “sew.”

c. Obligation

Modal verbs like “must” and “should” can be used to give advice and express obligations or requirements.

Example 1:

You should try to eat healthy food.

This sentence uses the modal verb “should.”
“Should” is used to give advice. In this case, the advice is about eating healthy.
The modal verb “should” is followed by the base verb “try.”

Example 2:

Students must complete their homework.

In this example, we see the modal verb “must.”
“Must” is used to express a requirement. In this case, the requirement is completing homework.
The base verb “complete” follows the modal verb “must.”

d. Permission

You can use modal verbs to ask for and give permission.

Example 1:

You may go to your friend’s party on Saturday.

This sentence includes the modal verb “may.”
“May” is used to give permission to go to the party.
The modal verb “may” is followed by the base verb “go.”

Example 2:

Can we swim at Grandma’s house after school?

In this example, we see the modal verb “can.”
Can is used to ask for permission to swim at grandmother’s house.
The modal verb “can” is followed by the base verb “swim.”

e. Ought

One other modal verb that we didn’t mention yet is the verb “ought.” “Ought” is different than other modal verbs because it has to be followed by an infinitive. An infinitive is a base verb with the word “to” in front of it.

Example 1:

We ought to give Jessica a birthday present.

This example uses the modal verb “ought.”
In this example, “ought” is used to express that it would be a good idea to give Jessica a present for her birthday.
“Ought” is followed by the infinitive “to give.”

Remember that modal verbs are auxiliary verbs, or helping verbs, that are most commonly used to talk about possibility or necessity. You can also use modal verbs to ask for and give permission, describe ability, and give advice.