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Modal Verbs in English Grammar

Modal Verbs Feature

What Are Modal Verbs?

Modal verbs are special verbs that add meaning to the main verb in a sentence. They show possibility, ability, permission, or obligation. 

Examples include “can,” “might,” “must,” and “should.” They don’t change form based on the subject and are followed by the base form of the main verb.

Uses of Modal Verbs

Modal verbs show what we can do, what we’re allowed to do, what we must do, and what might happen.

Here are examples of using modal verbs in all of these cases:

1. Expressing Possibility

Modal verbs can help you express the possibility and ability to do something. Here are some examples of both cases.

The Ability To Do Something:

We use  “can” and “could” as modal verbs to express ability:

Example 1: “I can swim.” This means swimming is something I’m capable of doing right now.

Example 2: “I could swim.” This suggests I had the ability to swim in the past. It might also mean they were able to swim under certain conditions.

Expressing Possibility To Do Something:

“May” and “might” are modal verbs that express possibility:

Example 1: “I may go to the party.” This means there’s a chance I will attend the party.

Example 2: “I might see a movie.” This implies there’s a chance of going to see a movie, but it’s not 100% certain.

These examples show how we use modal verbs to talk about our abilities. They also show the likelihood of future events.

2. Asking For or Giving Permission

We use  “can,” “could,” and “may” for asking permission. But we use “could” and “would” for making polite requests:

Asking Permission:

Here are examples of using modal verbs to ask permission:

Example 1: “Can I leave early today?” This directly asks for permission to leave sooner.

Example 2: “Could I use your phone?” This is a polite way to ask for permission, softer than “can.”

Example 3: “May I come in?” This is a formal and polite way to ask for permission.

Making Polite Requests:

These are polite requests using “could” and “would”:

Example 1: “Could you help me with this?” By using “could,” the request is made polite and less direct.

Example 2: “Would you mind opening the window?” Using “would” makes the request very polite and considers the other person’s comfort.

These examples highlight how modal verbs facilitate respectful communication. They are especially useful when seeking permission or making requests.

3. Expressing Obligation

“Must,” “have to,” and “ought to” express obligations. But there’s a subtle difference between each one.

Expressing Obligations:

We use modal verbs to express obligations. Here are some examples:

Example 1: “I must complete my work by 5 PM.” This implies a strong personal obligation or internal requirement.

Example 2: “I have to visit the doctor tomorrow.” This suggests a necessity based on a set of circumstances.

Example 3: “You ought to apologize.” This is a softer way to express an obligation, similar to giving advice.

If you want to show an obligation to do something, this is when you’d use “must”, “have to” or “ought to”.

Difference between “Must” and “Have To”:

Are there any differences between using “must” and “have to”? There is. But the difference is very subtle.

“Must” often expresses a personal obligation or something that feels necessary from the speaker’s point of view.

“Have to” implies an obligation imposed by external factors. For example, it could be laws, rules, or someone else’s expectations.

Again, the differences are minor. But understanding these nuances helps how we convey what we must do.

4. Expressing Advice and Giving Suggestions

We use “should,” “ought to,” and “had better” for giving advice. Whereas “shall” is for making suggestions in questions:

Giving Advice:

Consider using the following modal verbs when giving advice in real life situations:

Example 1: “You should see a doctor.” This is a common way to give advice, suggesting what someone should do.

Example 2: “You ought to take it easy.” Similar to “should,” but this sounds a bit more formal or strong.

Example 3: “You had better finish your homework.” This phrase implies a stronger recommendation. It has a hint of a negative consequence if the advice isn’t followed.

Making Suggestions and Questions:

You can also make suggestions and ask questions using modal verbs. Here’s a quick example of this.

Example 1:Shall we go for a walk?” Using “shall” in a question form like this offers a polite suggestion for a joint action.

These modal verbs offer guidance or suggest actions. Each one helps by speaking in a respectful and considerate manner.

Modal Verbs in Questions

Forming questions with modal verbs involves inverting the subject and the modal verb. Here are a couple of examples of how to form questions.

Example: “You can help me.”
Question Form: “Can you help me?”

“Can” is the modal verb, and “you” is the subject. In a statement, it might be “You can help me.” For a question, we invert them to “Can you help me?”

Example: “We should leave now”
Question Form: “Should we leave now?” 

“Should” is the modal verb, and “we” is the subject. The statement form would be “We should leave now.” To ask a question, swap their positions.

Example: “They will arrive on time”
Question Form: “Will they arrive on time?”

Here, “Will” is the modal verb, and “they” is the subject. The statement is “They will arrive on time.” For the question, the modal verb moves before the subject.

Example: “I must finish this today.”
Question Form: “Must I finish this today?”

“Must” is the modal verb, and “I” is the subject. In ‘statement form’, it’s “I must finish this today.” The question form requires inverting “must” and “I.”

When you invert the subject with the modal verb, it turns statements into questions. Now, you can ask questions about possibility, ability, necessity, and permission.

Negative Forms of Modal Verbs

Constructing negative sentences with modal verbs involves adding “not” after the modal verb. Here’s how it works and how the meaning changes with negation:

Example: “I cannot swim.”

The modal verb “can” expresses ability. Adding “not” changes the sentence to express a lack of ability. In this case, it’s being unable to swim.

Example: “You should not eat so much sugar.”

“Should” gives advice. With “not,” the advice is to avoid the action for better health or outcomes.

Example: “They must not leave the room.”

“Must” expresses a requirement or necessity. Adding “not” turns it into strong advice against an action. For example, it’s not advised to leave the room.

Example: “We might not go to the party.”

“Might” indicates possibility. By adding “not,” it expresses uncertainty. In this case, there is the possibility of not going to the party.

Negation with modal verbs shifts the sentences from stating an ability, advice, or possibility. Adding a negative form expresses prohibition, advice against something, or uncertainty.

Tips for Using Modal Verbs Correctly

Here are some of our top tips for using modal verbs correctly:

  • Try associating each modal with its primary function (e.g., “can” for ability, “should” for advice).
  • Always use the base form of the verb with modal verbs (e.g., “can go,” not “can goes”).
  • Misusing negative forms, like saying “mustn’t” when you mean “don’t have to,” can also lead to misunderstandings

We also suggest that you practice creating sentences in different contexts. Maybe, even in Toastmasters. Listening to movies, songs, and conversations can be really helpful for their nuances. Remember to practice in real-life applications because practice makes perfect.


Knowing how to use modal verbs helps add meaning in English. They tell us about what might happen, what we can do, and what we must do.

Do you have any questions about using modal verbs? We’d love to hear from you. Please share your thoughts in the comment section below.

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