Level A2

MUST

Le modal de l'obligation forte et de la déduction logique.

Formation

Affirmative ✓

Subject + MUST + verb

You must go.

She must be right.

Negative ✗

Subject + MUSTN'T + verb

You mustn't lie.

= Interdiction!

Question ?

MUST + subject + verb?

Must I go?

(peu commun)

When to Use MUST

⚠️

Strong Obligation

Obligation forte, règle

"You must wear a seatbelt."
🧠

Logical Deduction

Déduction logique (quasi certitude)

"She must be tired. (= I'm sure)"

Strong Recommendation

Recommandation forte

"You must try this restaurant!"
🚫

Prohibition (MUST NOT)

Interdiction formelle

"You must not smoke here."

🔥 MUST vs HAVE TO

MUST

Obligation personnelle / interne

"I must study harder."

(= Je pense que je dois...)

HAVE TO

Obligation externe / règle

"I have to wear a uniform."

(= C'est la règle)

💡 Tip: Au passé, on utilise HAD TO (MUST n'a pas de forme passée!)
"I had to work yesterday." ✅

⚠️ MUSTN'T vs DON'T HAVE TO

MUSTN'T

= Interdiction! Tu ne DOIS PAS

"You mustn't smoke here."

🚫 C'est interdit!

DON'T HAVE TO

= Pas obligé. Tu n'es pas obligé de...

"You don't have to come."

✅ Tu peux si tu veux, mais pas obligé

EdTech AI