Grammar · Modal Verbs

Possibility: May, Might & Could

Three ways to say “maybe”, and one negative that means “no way”. Learn them with the film Jumanji.

Grammar › Modal Verbs › Possibility: May, Might & Could

The rule in one sentenceUse may, might or could when something is possible but you are not sure — and use can’t when you are sure something is impossible.

About the film

Jumanji is a 1995 adventure film. Two children, Judy and Peter, move into an old house and find a strange board game in the attic. Every roll of the dice could bring something wild from the jungle into the house. The game might also be the answer to an old mystery: a boy called Alan disappeared there in 1969.

What does it do?

All three words mean “perhaps”. We use them when we are thinking about the present or the future, and we don’t know the answer. might is the most common in everyday speech. may is a little more formal. could is great for ideas and questions.

Be careful with the negatives. may not and might not mean “perhaps not”. But can’t means “I’m sure this is not true”. It is not a guess any more.

The next roll might bring a lion into the house.

The pieces move by themselves. It can’t be a normal game.

Peter may be too scared to play again.

That noise can’t be the wind. Something is upstairs.

Look at the first and third tiles. They are guesses, and the speaker isn’t sure. In the second and fourth tiles, the speaker has seen or heard something, so they feel certain.

Possible — maybe

Impossible — I’m sure it isn’t

+ It may / might / could be true.

+ (use “must” for “I’m sure it is”)

− It may not / might not be true.

− It can’t be true.

? Could it be true?

? Can it really be true?

past It might have been true.

past It can’t have been true.

In speech, people use the short forms of the negatives:

cannot → can’tcould not → couldn’tmight not → mightn’t (rare, British)“may not” has no short form

“There might be a monkey in the kitchen,” says Peter. “It can’t be a monkey,” says Judy. “We don’t live in a jungle!”
Peter is guessing. Judy is sure — but in Jumanji, being sure is a dangerous idea.

Visual guide

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Teacher Teddy’s illustrated guide to this rule is being drawn — the full swipe-through infographic will appear here soon.

How to make it

may / might / could — maybe

person+may / might / could+base verb

The game could be very dangerous.

No “to” after these words, and no -s.

−

Aunt Nora might not believe their story.

“Might not” = perhaps not. Don’t use “could not” here.

Could the game be magic?

For questions, “could” sounds the most natural.

can’t — I’m sure it’s not

person+can’t / couldn’t+base verb

The house is empty. Nobody can be upstairs.

“Nobody can” works like “can’t”.

−

It’s as big as a bird! That can’t be a normal mosquito!

The speaker has a clear reason to be sure.

Can this really be happening?

A question that shows great surprise.

When to use each one

may / might / could — a guess

The future: The next roll might be even worse.
The present: Alan could be somewhere in the jungle.
Formal warnings: This game may not be safe for children.
Ideas: We could ask someone for help.

can’t — almost certain

Clearly false: That can’t be the wind. The windows are closed.
Surprise: You can’t be serious!
Using the facts: She was here a minute ago. She can’t be far away.
The past: He couldn’t have known about the game.

Words that help: a guess or a fact?

Some words near the sentence show how sure the speaker is.

may / might / could → not sure

perhapsmaybepossiblyI’m not surethere’s a chancewho knows

can’t → sure it’s not true

impossibleno wayI’m sureclearlybecauseit doesn’t make sense

Common mistakes

❌ The game mights be dangerous.

✅ The game might be dangerous.

These words never take -s, even with he, she or it.

❌ Alan could to be alive.

✅ Alan could be alive.

No “to” after could, may or might.

❌ I’m not sure, but Nora can’t believe the story.

✅ I’m not sure, but Nora might not believe the story.

“I’m not sure” shows a guess, so use might not.

❌ The pieces move by themselves. It mustn’t be a normal game.

✅ The pieces move by themselves. It can’t be a normal game.

For “I’m sure it isn’t”, use can’t, not mustn’t.

One more thing

This part is a little harder. You can come back to it later.

To guess about the past, add “have” + past participle. It works with all these words.
✅ The game might have been in the attic for years. (maybe)
✅ It can’t have been the wind. Something broke the window. (sure it wasn’t)

Practice: choose the right word

Eight questions. Choose one answer. You get the answer, and why.

1. The next roll ___ bring something dangerous.

These words never take -s.

2. Be careful. The game ___ very dangerous.

No “to” after could.

3. I’m not sure, but Peter ___ want to play again.

You’re not sure → might not.

4. The pieces move by themselves! It ___ be a normal game.

You’re sure it isn’t normal → can’t.

5. ___ the noise be a monkey?

Questions about possibility usually use could.

6. Perhaps Nora is busy. She ___ have time to listen.

“Perhaps” shows a guess → may not.

7. Nora’s car is outside, so she ___ be at work.

The car is a clear reason → can’t.

8. Judy isn’t sure. The game ___ have been in the attic for years.

She isn’t sure → might have.

Your turn

Choose one ending. Then listen to your sentence.

This weekend, I might …

Tomorrow, it could …

Every sentence here is correct. Pick the one that is true for you. Say it out loud too!

Keep going

Next lessonPreposition + -ing →

More lessons

Modals of Deduction (Must, Can’t, Might) Modal Verbs of Speculation (Must Have, Might Have) Permission: Can, Could & May The Future Tense (Will, Going To)

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Possibility: May, Might & Could — English Grammar (B1)