🧭 Grammar · Modal Verbs
Permission: Can, Could & May
Learn how to ask for, give and refuse permission politely — from casual chats to formal notices.
Grammar › Modal Verbs › Permission: Can, Could & May
The rule in one sentenceUse can for everyday permission, could for polite requests, and may for formal or written permission — and remember that can’t usually refuses permission while may not is the formal way to forbid something.
Asking, giving and refusing permission
In English, three modal verbs let you talk about permission: can, could and may. They all mean roughly “is this allowed?” — but they sit at different levels of formality.
Can is the everyday choice. A teenager asks a parent Can I watch Thunderbolts* tonight?, and a friend tells another You can borrow my Weapons DVD whenever you want. It’s relaxed and direct, used constantly between people who know each other.
Could is can’s more polite cousin. It softens a request without changing the meaning: Could I take a photo with the Sinners poster in the lobby? sounds more considerate than “Can I…?”, which is why it’s the safer choice with strangers, teachers, or anyone you want to sound courteous with.
May is the formal option, common in written notices and careful speech. A cinema sign might read Guests may not bring outside food into the Shall We Dance? (1996) screening in Screen 4, and at a press event a journalist might begin, May I ask you about Rustin at today’s press conference?
🎬 Compare: “Can I sit here?” (casual, said to a friend queuing for The Fantastic Four: First Steps) vs. “May I take this seat?” (formal, said to a stranger at the Materialists premiere).
Same question, different register — can for everyday life, may for formal situations.
Refusing permission usually uses can’t in speech: You can’t bring your dog into the Cineworld screening of Paddington in Peru. In formal writing, may not takes over: Patrons may not record any part of Glory Road.
How to build it
Can — everyday permission
You can watch Till with your sister — it’s a powerful historical drama.
You can’t bring outside snacks into most Cineworld screenings of Superman (2025).
Can I sit here? The Any Given Sunday screening is about to start.
Could / May — polite & formal permission
You may take one photo before the screening of The Natural starts, sir.
You may not record any part of Kingdom of Heaven inside the cinema.
Could I ask you for an autograph, Mr Fassbender?
When to use which
Can — casual, everyday
- Friends and family: Can I borrow your One Night in Miami Blu-ray?
- General rules: You can watch a 12A film like Twilight if an adult is with you.
- Quick refusals: Sorry, you can’t use flash photography during The Wrestler.
Could / May — polite, formal
- Strangers or people you respect: Could I ask you which is better, Bull Durham or Da 5 Bloods?
- Written notices and signs: Guests may not bring drinks into the Draft Day screening in Screen 1.
- Official announcements: May I remind everyone that Marshall is starting shortly?
Signal phrases: your instant clue
Certain phrases signal that permission is the topic — learn to recognise them.
Asking permission
Giving or refusing permission
Visual guide
Teacher Teddy’s illustrated guide to this rule is being drawn — the full swipe-through infographic will appear here soon.
Common mistakes
❌ Can I to watch The Substance? It’s rated 18.
✅ Can I watch The Substance? It’s rated 18.
Modal + base verb — never add “to” after can, could or may.
❌ She cans go to the premiere of The Trial of the Chicago 7 with her sister.
✅ She can go to the premiere of The Trial of the Chicago 7 with her sister.
Modal verbs never take -s, even with he/she/it.
❌ I could watch the special preview of Loving last night — my friend got me a ticket.
✅ I was allowed to watch the special preview of Loving last night.
For one specific permitted event in the past, use “was/were allowed to” — “could” is for general or repeated past permission.
❌ May you let me sit in the front row for A Different Man?
✅ Could you let me sit in the front row for A Different Man?
“May I…?” asks permission for yourself — to ask someone else to do something, use “could/can you…?” instead.
Exceptions & tricky cases
1. Can’t has two jobs. It can refuse permission or state impossibility — context tells them apart.
✅ You can’t watch When We Were Kings — it’s not suitable for younger viewers. (permission)
✅ You can’t have watched it already — it doesn’t open until Friday! (impossibility)
2. Could for repeated past permission. Unlike the one-off case above, “could” is correct for permission that applied again and again.
✅ When I was a teenager, I could watch Sing Sing, or any other film suitable for my age, at my local cinema after school.
3. Formal signs prefer “may not”. Written notices almost always use the full form, not a contraction.
✅ Patrons may not photograph the screen during Emilia Pérez. — not “can’t” or “mayn’t”.
4. “May” shifts to “might” in reported speech. When you report what someone said, may usually backshifts.
✅ The usher said we may not use flash photography during the King Richard screening. → The usher said we might not use flash photography during the King Richard screening.
Practice: choose the right form
Eight quick questions about asking, giving and refusing permission at the cinema.
1. ___ take a photo with The Iron Claw poster in the lobby?
In questions, the modal comes before the subject: Can + I + verb?
2. You ___ watch Cuckoo — it’s not suitable for someone your age.
It’s not appropriate for your age yet → can’t.
3. ___ I ask you something about The Power of the Dog, Ms Campion?
Modal + base verb — never add “to” after could.
4. When I was ten, I ___ watch Flow without an adult — it was suitable for my age.
A past situation needs the past form of can: could.
5. I ___ watch the special one-off screening of Blitz last night — my friend who works at the cinema let me in.
One specific permitted past event needs “was/were allowed to”, not “could”.
6. A sign at the premiere afterparty for The Woman King said: “Guests ___ enter without an official pass.”
Formal notices use the full “may not” — “mayn’t” is old-fashioned and rarely used.
7. You ___ film the actors during the Civil War red carpet — it’s strictly forbidden.
The standard negative is written as one word, “cannot”.
8. The usher told us we ___ use flash photography during the Concussion screening.
In reported speech, “may” usually backshifts to “might”.
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