Acciones prohibidas: Cómo usar Mustn't
para decir que algo estáestrictamente prohibido
, que no se permite o es una muy mala idea".
Grammar Rule in 30 Seconds
Use 'mustn't' to say something is strictly forbidden or against the rules.
- Use 'mustn't' + base verb (no 'to'): 'You mustn't smoke here.'
- It never changes form: 'He mustn't', 'They mustn't' are the same.
- It means 'don't do it'—it is not the same as 'don't have to'.
Overview
mustn't es un paso fundamental para cualquier estudiante de nivel A2 que desee comunicarse con precisión y autoridad en inglés. Esta palabra, que es la contracción de must not, no es simplemente una opción más en el vocabulario; es la herramienta definitiva para expresar prohibición absoluta. Imagina que estás caminando por un museo en Londres o leyendo las normas de seguridad en un aeropuerto internacional: las acciones que están terminantemente prohibidas siempre aparecerán acompañadas de este verbo modal.mustn't como no debes o está prohibido. Sin embargo, el matiz en inglés es mucho más fuerte que un simple consejo. Mientras que en español a veces decimos no deberías hacer esocomo una sugerencia amable, en inglés, el uso de
mustn't elimina cualquier espacio para la interpretación o la elección personal.mustn't es vital porque nos ayuda a evitar malentendidos culturales. En muchos países de habla inglesa, las reglas se consideran absolutas. Si alguien te dice You mustn't enter, no te está pidiendo que lo consideres; te está informando de una restricción total.mustn't es, en muchos sentidos, más sencillo que el de los verbos en español. Como es un verbo modal, tiene propiedades únicas que lo hacen muy predecible. La mayor ventaja para ti es que, a diferencia del español, donde conjugamos el verbo deber para cada persona (yo no debo, tú no debes, nosotros no debemos), en inglés la forma es invariable.- 1Sin conjugación por persona: No importa si hablas de ti mismo, de tu jefe o de un grupo de amigos. Siempre usarás
mustn't. No existe el*mustn'ts*ni nada parecido. Esto simplifica enormemente tu carga mental al hablar. - 2Uso del infinitivo sin
to: Esta es una de las reglas de oro de los modales. Después demustn't, el verbo principal siempre va en su forma base (el infinitivo sin elto). En español decimosno debes fumar
, y en inglés decimosyou mustn't smoke. Nota que no decimos*mustn't to smoke*ni*mustn't smoking*. - 3Negación directa: No necesitas auxiliares como
do,doesodid. La negación está integrada en el propio modal. Esto es una gran ventaja, ya que elimina la confusión de elegir el auxiliar correcto según el tiempo verbal.
Mustn't) |I/You/He mustn't (Igual para todos) |no) | No usa don't/doesn't |smoke, eat) |mustn't se enfoca en la obligación negativa. Es decir, tienes la obligación de *no* hacer algo. Es como si el semáforo estuviera en rojo permanente para esa acción específica.mustn't es extremadamente lineal. Al ser un nivel A2, lo ideal es que memorices este patrón como una fórmula matemática que nunca cambia. No hay excepciones basadas en el sujeto ni en el tipo de verbo que le sigue.mustn't + Verbo en forma base + ComplementoI mustn't forget my passport.(No debo olvidar mi pasaporte.)You mustn't park here; it's a private entrance.(No debes estacionar aquí; es una entrada privada.)He mustn't tell anyone the secret.(Él no debe contarle el secreto a nadie.)She mustn't eat peanuts; she is allergic.(Ella no debe comer cacahuates; es alérgica.)We mustn't make noise in the library.(No debemos hacer ruido en la biblioteca.)They mustn't arrive late for the meeting.(Ellos no deben llegar tarde a la reunión.)
must not. Ambas significan lo mismo, pero must not suena mucho más enfático y severo. En una conversación diaria, en un WhatsApp o en un correo electrónico de trabajo, mustn't es la opción más natural.t en mustn't es prácticamente muda. No intentes pronunciar cada letra con fuerza. Suena algo así como /mʌsnt/. Si intentas pronunciar la t del medio, te costará mucho fluir en la frase. Escúchalo en tu mente como una sola unidad de sonido.mustn't? No es una palabra que uses para dar consejos ligeros a un amigo sobre qué película ver en Netflix. Se reserva para situaciones donde hay consecuencias o reglas claras.You mustn't smoke on the plane.(Es una ley federal de aviación).Drivers mustn't use their phones while driving.(Es una regla de tránsito).
You mustn't touch the electrical wires.(¡Peligro de descarga!).Children mustn't play near the swimming pool alone.(Advertencia de seguridad vital).
I mustn't fail this exam.(Me lo digo a mí mismo porque es crucial).We mustn't lose this client.(Es una prioridad absoluta para el equipo).
You mustn't tell Sarah about the surprise party.(Si lo haces, arruinas la sorpresa).Employees mustn't share their passwords.(Regla de ciberseguridad).
You mustn't interrupt the speaker during the presentation.(Es una norma de cortesía profesional).We mustn't be rude to the customers.(Es la base del servicio al cliente).
Mustn't con Don't have to (¡El más peligroso!)no tienes que para decir que algo está prohibido. En inglés, estas dos expresiones son polos opuestos.Mustn't= Está prohibido. No tienes opción. (Prohibición).Don't have to= No es necesario, pero si quieres, puedes hacerlo. (Falta de necesidad).
You don't have to smoke here, le estás diciendo a la persona: No es obligatorio que fumes aquí (puedes no hacerlo si no quieres, pero si quieres, adelante). Si lo que quieres es prohibirlo, debes decir
You mustn't smoke here.to después de mustn'tdeber a(aunque no siempre) o simplemente estamos acostumbrados a que los infinitivos lleven
to en inglés (como want to), tendemos a decir: *I mustn't to go*.to. La forma correcta es siempre I mustn't go.must como si fuera un verbo normal: *I don't must*.Must es su propio auxiliar. No necesita a do ni a does. La forma negativa es única: mustn't.mustn't encaja en el rompecabezas de las obligaciones en inglés.Mustn't | Prohibición. No lo hagas. | You mustn't go. | Máxima (100%) |Can't | Incapacidad / No permiso. No puedes. | You can't park here. | Alta (90%) |Shouldn't | Consejo negativo. No deberías. | You shouldn't eat so much sugar. | Media (Sugerencia) |Don't have to | Sin obligación. No hace falta. | You don't have to pay now. | Baja (Elección) |mustn't suena más a una orden directa o una ley moral/oficial, mientras que can't a menudo se refiere a que algo no es posible según las reglas externas o la lógica. Para un estudiante de A2, usar mustn't te hará sonar mucho más preciso cuando quieras enfatizar que algo es una regla estricta.mustn't para hablar del pasado?Mustn't solo se usa para el presente o el futuro inmediato. Si quieres decir que algo estaba prohibido en el pasado, debes usar weren't allowed to o couldn't. Por ejemplo: We weren't allowed to use calculators in the exam (No se nos permitía usar calculadoras en el examen).mustn't muy formal?can't (You can't do that!), pero mustn't es perfectamente aceptable y muy común en el entorno laboral y educativo.mustn't?mustn't, lo más común es aceptar la regla con un simple I understand, Okay, I won't, o I'm sorry, I didn't know. No necesitas repetir el modal en tu respuesta.mustn't en preguntas?*Mustn't I...?*. Para preguntas sobre prohibición o permiso, preferimos usar Can't I...? o Shouldn't I...?. Por lo tanto, enfócate en usar mustn't principalmente en oraciones afirmativas negativas (prohibiciones).mustn't. Recuerda: es tu señal de Stop gramatical. Úsala con confianza cuando las reglas sean claras y no haya lugar para excusas. ¡Mucho éxito en tu camino al nivel B1!Mustn't Conjugation (All Subjects)
| Subject | Modal | Base Verb | Example |
|---|---|---|---|
|
I
|
mustn't
|
smoke
|
I mustn't smoke.
|
|
You
|
mustn't
|
smoke
|
You mustn't smoke.
|
|
He/She/It
|
mustn't
|
smoke
|
She mustn't smoke.
|
|
We
|
mustn't
|
smoke
|
We mustn't smoke.
|
|
They
|
mustn't
|
smoke
|
They mustn't smoke.
|
Contractions
| Full Form | Contraction | Usage |
|---|---|---|
|
must not
|
mustn't
|
Very common in speech and informal writing.
|
Meanings
Used to express that an action is prohibited, forbidden, or a very bad idea according to rules, laws, or social norms.
Strict Prohibition
Official rules or laws that stop you from doing something.
“Passengers mustn't talk to the driver.”
“You mustn't park your car in front of the hospital entrance.”
Strong Advice Against
Telling someone not to do something because it is dangerous or a mistake.
“You mustn't tell Sarah about the party; it's a surprise!”
“You mustn't forget to take your passport to the airport.”
Negative Deduction (Rare)
Expressing a logical conclusion that something is likely not true (more common in British English).
“He mustn't be home yet; his car isn't in the driveway.”
“They mustn't like the food; they haven't eaten anything.”
Reference Table
| Sujeto | Modal Negativo | Verbo Base | Contexto |
|---|---|---|---|
|
I
|
mustn't
|
forget
|
Recordatorio personal
|
|
You
|
mustn't
|
share
|
Regla de seguridad
|
|
He
|
mustn't
|
enter
|
Prohibición estricta
|
|
She
|
mustn't
|
know
|
Secreto/Social
|
|
We
|
mustn't
|
late
|
Regla de grupo (✗ incorrecto)
|
|
They
|
mustn't
|
park
|
Regla legal
|
|
It
|
mustn't
|
happen
|
Advertencia general
|
Espectro de formalidad
Personnel must not enter this restricted area. (A restricted room)
You mustn't go in there. (A restricted room)
You can't go in there. (A restricted room)
Stay out! No entry! (A restricted room)
El Mundo de 'Mustn't'
Reglas
- No smoking You mustn't smoke.
- No parking You mustn't park.
Seguridad
- Danger You mustn't touch.
'Mustn't' vs. 'Don't Have To'
¿Es 'Mustn't'?
¿Está en contra de la ley o una regla?
¿Es opcional?
Cuándo decir 'Mustn't'
Apps/Tecnología
- • Compartir contraseñas
- • Publicar spoilers
- • Trollear
Viajes
- • Olvidar identificación
- • Fumar en aviones
- • Abrir puertas
Ejemplos por nivel
You mustn't swim here.
You are not allowed to swim here.
He mustn't eat chocolate.
He is not allowed to eat chocolate.
We mustn't be late.
It is important that we are not late.
You mustn't shout.
Do not shout.
You mustn't use your phone in class.
Using your phone is against the rules.
Drivers mustn't park on the grass.
Parking on the grass is forbidden.
You mustn't forget your keys again.
It's a bad idea to forget your keys.
We mustn't tell him the secret.
We are forbidden from telling him.
You mustn't drink the water; it's not potable.
The water is unsafe to drink.
Visitors mustn't feed the animals in the zoo.
Feeding animals is strictly prohibited.
You mustn't take photos inside the museum.
Photography is not permitted.
We mustn't let this opportunity pass us by.
It would be a mistake to ignore this.
One mustn't assume that all students learn the same way.
It is wrong to make that assumption.
You mustn't speak to your manager in that tone.
That way of speaking is unacceptable.
The medicine mustn't be taken on an empty stomach.
It is dangerous to take it without food.
We mustn't underestimate the complexity of the problem.
We should not think it is easier than it is.
The jury mustn't be influenced by media coverage.
It is legally required that they remain neutral.
Such behavior mustn't be tolerated in a civilized society.
Society should not allow this.
He mustn't have heard the news, or he'd be here.
It is logically likely he hasn't heard.
We mustn't lose sight of our original objectives.
We must remain focused on our goals.
The sanctity of the contract mustn't be compromised.
The contract must remain untouched.
One mustn't trifle with the emotions of others.
It is morally wrong to play with feelings.
The archives mustn't be accessed without explicit written consent.
Access is strictly controlled.
The delicate balance of the ecosystem mustn't be disturbed.
Human interference is prohibited.
Fácil de confundir
Learners think 'mustn't' is the opposite of 'must' in terms of necessity. They use 'mustn't' when they mean 'it's not necessary'.
Both are used for advice, but 'mustn't' is a command while 'shouldn't' is a suggestion.
In many contexts they overlap, causing confusion about which one to pick.
Errores comunes
You mustn't to run.
You mustn't run.
He musts not go.
He mustn't go.
You don't must smoke.
You mustn't smoke.
I mustn't to forget.
I mustn't forget.
It's Sunday, so I mustn't work.
It's Sunday, so I don't have to work.
You mustn't parking here.
You mustn't park here.
Mustn't you go now?
Don't you have to go now?
Yesterday I mustn't go out.
Yesterday I wasn't allowed to go out.
You mustn't have a license to drive.
You must have a license to drive.
He mustn't be the thief; he was with me.
He can't be the thief; he was with me.
Patrones de oraciones
You mustn't ___ in the ___.
We mustn't forget to ___.
It's a secret, so you mustn't ___.
The ___ mustn't be ___.
Real World Usage
You mustn't carry liquids over 100ml.
You mustn't tell him about the surprise party!
Employees mustn't use personal phones during shifts.
You mustn't turn right on a red light here.
Drivers mustn't open the food packaging.
Users mustn't post copyrighted content.
La trampa del 'To'
EE. UU. vs. Reino Unido
suena más natural en Nueva York queYou mustn't park here".
Presión social
Smart Tips
Use the full form 'must not' instead of the contraction 'mustn't' to sound more authoritative.
Use 'mustn't' for strong personal advice to friends.
Delete the 'to' immediately. Modal verbs are always followed by the base verb.
Ask yourself: 'Is it okay if I do this?' If the answer is NO, use 'mustn't'. If the answer is YES, use 'don't have to'.
Pronunciación
The Silent 'T'
In the word 'mustn't', the first 't' is silent. It sounds like 'MUSS-unt'.
Contraction Stress
The stress is usually on the first syllable: MUSS-nt.
Falling Intonation for Commands
You mustn't ↘ touch it.
Conveys a firm, final rule.
Memorízalo
Mnemotecnia
Mustn't is a 'Must-Not'—if you do it, you're in a knot!
Asociación visual
Imagine a giant red 'X' taped over your mouth or hands. That 'X' is the word 'mustn't' stopping you from doing something forbidden.
Rhyme
When the sign says 'Mustn't', don't be a fool. Follow the law and follow the rule!
Story
Little Red Riding Hood's mother said: 'You mustn't leave the path.' Red Riding Hood did leave the path, and she met the wolf. The word 'mustn't' was there to keep her safe from the wolf.
Word Web
Desafío
Look around your room or office. Find 3 things you 'mustn't' do (e.g., 'I mustn't spill coffee on my laptop'). Say them out loud.
Notas culturales
Mustn't is very common in the UK for rules and strong advice. It sounds natural and polite yet firm.
Americans often find 'mustn't' sounds a bit old-fashioned or very formal. They usually use 'can't' or 'shouldn't' instead.
In legal documents, 'must not' (the full form) is used to create a mandatory prohibition.
From Old English 'mōtan' (to be allowed/to have to). The negative 'not' was added later to create prohibition.
Inicios de conversación
What are some things you mustn't do in a library?
Tell me about a strict rule at your workplace or school.
If you were a parent, what is one thing your children mustn't do?
Discuss the ethical things a doctor mustn't do.
Temas para diario
Errores comunes
Test Yourself
If you are in a library, which sentence is correct?
You ______ share your password with strangers.
Find and fix the mistake:
She mustn't to use her laptop in the exam.
Score: /3
Ejercicios de practica
8 exercisesWhich sentence is correct?
The museum is free. You ___ pay.
Find and fix the mistake:
You mustn't smoking in the hospital.
tell / mustn't / secret / you / the
Match: 1. No Entry, 2. No Cameras, 3. No Food
It is forbidden to park here.
'Mustn't' is the same as 'Don't have to'.
A: Can I tell John? B: No, you ___! It's a surprise.
Score: /8
Practice Bank
10 exerciseseat / mustn't / here / you
Du darfst dein Handy im Kino nicht benutzen.
Match the meaning
Students ______ cheat during tests.
Which is more formal for a legal document?
He mustn't drinks coffee at night.
forget / mustn't / they / ID / their
Pick the scenario for 'mustn't':
I ______ forget my mom's birthday!
We mustn't lose the keys.
Score: /10
Preguntas frecuentes (8)
It is less common than in British English. Americans usually say `can't` or `not allowed to`. However, Americans still understand it perfectly.
No, `mustn't` has no past form. You should use `wasn't allowed to` or `couldn't`. For example: 'I wasn't allowed to go out yesterday.'
`Mustn't` is a strong rule or prohibition. `Shouldn't` is just advice. If you say `mustn't`, it means 'don't do it or there will be trouble!'
`Must not` is more formal and emphatic. You will see it on official signs or in legal contracts to make the rule sound very serious.
It is possible (e.g., 'Mustn't we tell him?'), but it sounds very old-fashioned. It's better to use 'Shouldn't we...?' or 'Don't we have to...?'
No. Like all modal verbs, it stays the same for all subjects. `I mustn't`, `she mustn't`, `they mustn't`.
It can be quite blunt. To be more polite, you might say 'I'm afraid you can't...' or 'Please don't...'
Yes, in British English, it can be used for logical deduction (e.g., 'He mustn't be at home'). But `can't` is much more common for this.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
nicht dürfen
German 'muss nicht' is NOT English 'mustn't'.
no deber / prohibido
Spanish often uses 'no puedes' (can't) where English uses 'mustn't'.
ne pas devoir / il ne faut pas
French impersonal 'il ne faut pas' is much more common than the English 'one mustn't'.
〜てはいけない (~te wa ikenai)
Japanese has different levels of politeness for prohibition that English lacks.
لا يجب (la yajib)
Arabic often uses the same phrase for 'mustn't' and 'shouldn't'.
禁止 (jìnzhǐ) / 不准 (bùzhǔn)
Chinese uses full verbs/adjectives rather than a modal auxiliary.
Learning Path
Prerequisites
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