You must wear a seat belt.
Grammar · A1
Must, mustn't and have to
Understand a rule: you need to do it, you cannot do it, or it is your choice.
You must wear a seat belt.
01 · The idea
Look. Compare these examples.
Understand a rule: you need to do it, you cannot do it, or it is your choice.
No photos. You mustn't take photos.
The trip is optional. You don't have to come.
02 · More examples
Look at what changes.
Must and have to can tell us what is needed.
You must wear a seat belt.
We have to bring a ticket.
She has to start early.
Mustn't means no: you are not allowed to do it.
No photos. You mustn't take photos.
No smoking. You must not smoke here.
Must not = mustn't.
Don't have to means you can do it, but you do not need to.
The trip is optional. You don't have to come.
Lunch is here. She doesn't have to bring food.
Do we have to pay?
03 · Build a sentence
Make a choice. See what changes.
Change one choice at a time. Watch the sentence blocks.
You must take photos.
What is the rule?
What action?
04 · Try it together
Choose the correct answer.
Quick check 1
You must ___ a helmet.
Is the action needed? Compare I have to and she has to.
Quick check 2
The sign says No swimming. You ___ swim here.
Is this a rule saying the action is forbidden?
Quick check 3
The visit is optional. You ___.
Is the action optional, rather than forbidden?
05 · Real-life English
Use it in a conversation.
A: Can I take photos? B: You mustn't use a flash. Photos without a flash are OK. A: Do I have to buy a ticket? B: No, you don't have to pay. It's free.
Make two rules for a museum: one thing people cannot do and one thing they do not need to do.
A: Do you have to wear a uniform? B: Yes, I do. I have to wear it every day. A: And on Saturday? B: I don't work on Saturdays.
Ask about a rule at school, work or home. Say what is needed and what is optional.
06 · Common mistakes
Which sentence is correct?
07 · Keep this
The lesson in three small steps.
You need to do it
You must wear a seat belt. She has to wear one too.
Not allowed
No photos: you mustn't take photos.
It is your choice
The trip is optional: you don't have to come, but you can.
08 · Practice
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