must and mustn't (rules)
The grammar of rules — and children adore rules they get to announce. You must listen. You mustn't run. Instant classroom law.
From age 8Building sentences →
✏️ The pattern
- Saying it
- You must listen.
- Saying no
- You mustn't run.
- Asking
- Must I go? (rare)
- Short answer
- Yes, you must.
🗣️ Sentences a child can say
Tap any sentence to hear it. Every one uses words from a topic pack you already have.
🩹 What you will actually hear
The three mistakes that come up in every class, and what is behind each one.
You must to listen.You must listen.
Must is a modal — it connects straight to the bare verb. The to habit comes from want to and need to; modals travel lighter.
He musts go.He must go.
Modals never take -s, even for he and she. They are the one corner of English where third person gets no special treatment.
🎯 How to teach it
- 1
Write the class rules together, in English, on a poster the class signs. Rules children author are rules children quote — in English, at each other, forever.
- 2
Play rule-or-no-rule with picture cards: pool, library, zoo. Each place demands its must and mustn't; the class supplies them.
- 3
Let mustn't sound dramatic: whisper it, widen your eyes. The emotional colour is real — mustn't is stronger than don't — and drama encodes it.
🗂️ Topic packs that pair with this
Same structure, words your class already knows — no new vocabulary needed.
💬 Questions teachers ask
Must or have to first?
Must first: no endings, no do-support, pure rule energy. Have to arrives a level later as the everyday twin, and the pair sorts itself out with use.
Is mustn't too strong for a kind classroom?
Aim it at actions, never at children: 'We mustn't push' beside a picture, said as a shared law of physics. Strong grammar can carry a gentle voice.