Grammar · Modal Verbs
Modals of Obligation & Permission (Must, Have To, Can)
Some small words tell you what you need to do, and others tell you what you are allowed to do. Learn them with the film The Devil Wears Prada 2.
Grammar › Modal Verbs › Modals of Obligation & Permission (Must, Have To, Can)
The rule in one sentenceUse must or have to when something is necessary, and can or could when something is allowed.
About the film
The Devil Wears Prada 2 is a 2026 comedy-drama and the sequel to the 2006 film, with Meryl Streep and Anne Hathaway. Twenty years later, Andy Sachs has to find new work, and she goes back to Runway magazine as an editor. Miranda Priestly didn’t choose her, but now the two women have to work together again. Andy can use her skills as a reporter, but the fashion world has its own rules.
What does it do?
These words go before another verb and change its meaning. must and have to say that something is necessary. There is a rule, or you have no choice.
can and could say that something is allowed. We use them to ask, give or refuse permission. could is a little more polite when you ask.
Look at the first and second tiles. Andy has no choice — it is part of her job, so we use has to. In the second tile, someone is asking if something is OK, so we use can.
In speaking, we usually use short forms:
Andy has to go to the meeting. Andy can go to the meeting.
In the first sentence, she has no choice. In the second, she is allowed to go — but she can stay at her desk if she wants.
Visual guide
Teacher Teddy’s illustrated guide to this rule is being drawn — the full swipe-through infographic will appear here soon.
How to make it
must / have to — it’s necessary
Andy has to learn the new rules at Runway.
You don’t have to wear a suit. Jeans are fine.
“Don’t have to” = it’s not necessary. “Mustn’t” = it’s not allowed.Do I have to finish this today?
For questions, use “Do / Does … have to”.can / could — it’s allowed
You can use my desk while I’m out.
Visitors can’t take photos in the office.
“Can’t” means it is not allowed.Could I leave a little early today?
“Could” is softer and more polite than “can”.When to use each one
must / have to — necessary
can / could — allowed
Words that help: necessary or allowed?
These words often appear near each meaning. They can help you choose.
must / have to → necessary
can / could → allowed
Common mistakes
❌ Andy musts work late tonight.
✅ Andy must work late tonight.
“Must” never changes. There is no “-s”, even after he, she or it.
❌ Can I to use your phone?
✅ Can I use your phone?
Don’t put “to” after “can” or “must”. Only “have to” has “to”.
❌ Yesterday I must stay at work until ten.
✅ Yesterday I had to stay at work until ten.
“Must” has no past form. For the past, use “had to”.
❌ You mustn’t come to the party if you’re tired.
✅ You don’t have to come to the party if you’re tired.
It’s your choice, not a rule. “Mustn’t” would mean it’s not allowed.
One more thing
This part is a little harder. You can come back to it later.
“Must” or “have to”? They are very close. must often comes from you — your own idea of what is important. have to often comes from outside — a boss, a law or a timetable.
✅ I must get more sleep. (my own idea)
✅ I have to be at the office at eight. (my boss’s rule)
Practice: choose the right word
Eight questions. Choose one answer. You get the answer, and why.
1. Andy ___ work with Miranda again. It’s part of her new job.
She has no choice → has to.
2. ___ I sit here? Is this seat free?
You are asking if it’s OK → can.
3. You ___ smoke in the office. It’s against the rules.
It’s not allowed → mustn’t.
4. It’s Saturday, so I ___ get up early.
It’s not necessary, but it’s OK → don’t have to.
5. Yesterday I ___ stay at work until ten.
For the past, use “had to”.
6. ___ I open the window, please? It’s very hot.
A polite request for permission → could.
7. Children ___ swim here without an adult. It’s dangerous.
It’s not allowed → can’t.
8. ___ I have to wear a suit to work?
Questions with “have to” use “do” → Do I have to …?
Your turn
Choose one ending. Then listen to your sentence.
Every sentence here is correct. Pick the one that is true for you. Say it out loud too!
Keep going
This film’s lesson
More lessons
Now hear it in the film
You have just learned modals of obligation and permission with The Devil Wears Prada 2. Now hear the whole film explained in English.
The full listening episode on the same film — a slow, clear movie review with the language used in real speech, and a free transcript.
IntermediateEpisode 10Watch on YouTube