When and Why to Use Modals
Essential Question
How can we use modal verbs to help express necessity, uncertainty, possibility, or permission?
Grammar in the World
What Do I Know?
Use the interactive below to see how much you already know about using modals:
Building Blocks
Grammar is a complex system and structure of language. Mizzou Academy Grammar Lab spotlights one skill (or block) at a time, but it’s often helpful to see how a skill works together with other, related blocks to build the language structure as a whole. You may find the following resource topics helpful as context for this lesson:
- Verbs
- Verb Tenses
- Subject-Verb Agreement (Auxiliary Verbs and Questions)
- Progressive Modals
- Perfect Modals
Learn About Modals
Read each of the following sentences. Which one is correct?
- You must practice using modal verbs.
- You might practice using modal verbs.
- You could practice using modal verbs.
- You should practice using modal verbs.
- You can practice using modal verbs.
- You will practice using modal verbs.
You probably guessed it–all of these sentences are correct. Yet, they all mean something different.
Modal verbs are an important type of verb that allows us to get at subtle nuances in language. They help other verbs in a sentence, and their main job is to express a condition in a sentence.
There are 9 modal verbs, which you are already familiar with.
Each of these verbs helps another verb express a certain condition. Look at this chart, and while you view the examples, notice the patterns you see with these modal verbs.
|
Modal Verb |
Purpose |
Example |
|
Will Might May Can Could Must |
likelihood–the chance (small or big) of something happening in the future |
You must be exhausted! We might go to the zoo tomorrow. We may go home early today. |
|
Must (Have to) |
obligation–something that has to happen |
You must take off your shoes at the door.
|
|
Can Could May |
permission–something allowed to happen |
You can watch a movie after you finish your homework. You may go to Grandma’s house after school if you like. |
|
Can |
ability–whether a thing can be done or not |
I can eat an entire pizza by myself. I could count to 1,000 by the time I was three years old. |
|
Should |
advice–suggestion |
You should go outside for some fresh air.
|
|
Will Shall |
future–a prediction of what may happen |
You will learn more about modals by the end of this lesson. *Shall is a more formal form of “will.” It’s common in Britain and rarely used in the United States. |
Here are some important things you might already notice about modals:
They're auxiliary verbs
They are auxiliary verbs. Modals are auxiliary verbs. They always “help” another verb in the sentence:
- You should see the musical Hamilton!
- I think it might be the best performance I’ve seen!
|
Note: All modals are auxiliary verbs, but not all auxiliary verbs are modals. For example, these are not modals:
You can recognize modals because they help express condition (likelihood, permission, obligation) in a sentence, rather than state of being or action. |
Not number specific
Modals always take the same singular and plural form. These verbs agree with any subject.
For instance, if we don’t use a modal, we change the verb to agree with the subject:
- I sing the songs every day.
- He sings the songs every day.
Modals, on the other hand, stay the same no matter what. For example:
Incorrect
- He wills sings the songs every day
Correct:
- He/She will sing the songs every day.
- We will sing the songs every day.
- They will sing the songs every day.
- I/You will sing the songs every day.
No infinitives
Modals don’t have infinitives. Never add “to” in front of a modal.
For instance, without a modal, I might use an infinitive form:
- I invited my friend to see the musical with me.
Modals, though, never have the word “to” in front of them.
Incorrect:
- We to could see the musical next weekend.
- You to should see the musical again.
Correct:
- We could see the musical next weekend.
- You should see the musical again.
Showing certainty
Modals are used to show how sure, or certain, we are about something.
Absolutely Certain:
I am confident about an action, event, or idea.
- Lin-Manuel Miranda will perform tomorrow.
- Lin-Manuel can rap and dance.
Very certain / High Degree of Probability
While I'm not 100% sure about my statement, I believe the action, event, or idea is likely.
- Lin-Manuel Miranda must be a talented artist.
- Lin-Manuel Miranda should be on stage soon.
Somewhat certain / Low Degree of Probability
I am either only partially certain, or I have some doubt about whether the action, event, or idea is likely.
- I may take pictures if they allow it.
- I might be lucky enough to get front-row seats.
- Lin-Manuel Miranda could sign autographs after the show.
Substitutes
Ought, had better, and need all work similarly to “should” and give advice or a command:
- You ought to go outside for some fresh air.
- You need to do your homework first.
- You had better do it quickly!
Do I Get It?
Use the interactive below to check how much you learned about modals:
| Note: there are two exercises in the interactive, below. When finished with Part 1, click to the next slide for Part 2. |