La pasiva con verbos modales en inglés
Verbos modales en voz pasiva: expresa posibilidad, obligación y consejo de forma indirecta
Los verbos modales (can, could, must, should, may, might, would) añaden matices de posibilidad, obligación, permiso o consejo. Cuando los combinamos con la voz pasiva, podemos expresar esos mismos matices pero enfocándonos en la acción o el objeto receptor. Por ejemplo: «You must finish the report» (activa) → «The report must be finished» (pasiva).
🎯 En este post aprenderás: La estructura fija modal + be + past participle para todos los modales, ejemplos en presente y pasado (modal + have been + past participle), diferencias de significado entre modales, y 5 ejercicios para dominar esta estructura intermedia-avanzada.
📋 Estructura básica: Modal + be + past participle
⚙️ La fórmula universal para la pasiva con modales
Los verbos modales en inglés nunca cambian de forma (no añaden -s en tercera persona, no tienen pasado regular, no usan «to» después). En la pasiva, simplemente añadimos «be» (en su forma base) y el past participle del verbo principal.
📌 Transformación paso a paso
Activa con modal: You must clean your room.
Paso 1: El objeto «your room» pasa a ser sujeto de la pasiva.
Paso 2: El modal «must» se mantiene igual.
Paso 3: Añadimos «be» después del modal.
Paso 4: El verbo principal «clean» se convierte en participio pasado «cleaned».
Paso 5 (opcional): El agente «by you» puede añadirse o no.
Pasiva: Your room must be cleaned (by you).
📊 Tabla completa: Modales en pasiva (presente/futuro)
| Modal | Significado | Ejemplo activo | Ejemplo pasivo |
|---|---|---|---|
| Can | Capacidad / posibilidad | Someone can fix this. | This can be fixed. |
| Could | Posibilidad / habilidad pasada | They could solve the problem. | The problem could be solved. |
| May | Posibilidad (formal) / permiso | You may leave the room. | The room may be left. |
| Might | Posibilidad remota | Someone might steal your bike. | Your bike might be stolen. |
| Must | Obligación fuerte | You must complete the form. | The form must be completed. |
| Should | Consejo / recomendación | You should take this medicine. | This medicine should be taken. |
| Would | Condicional / cortesía | I would send the email. | The email would be sent. |
| Have to (semi-modal) | Obligación (externa) | You have to do it. | It has to be done. |
| Need to | Necesidad | You need to clean the car. | The car needs to be cleaned. |
⏪ Pasiva con modales en pasado: Modal + have been + past participle
Para expresar posibilidad, obligación o consejo sobre acciones pasadas (ya ocurridas o no), usamos modal + have been + past participle. Esta estructura equivale a los modales en pasado de la voz activa.
| Modal pasado | Significado | Ejemplo activo | Ejemplo pasivo |
|---|---|---|---|
| Could have | Posibilidad pasada no realizada | They could have saved him. | He could have been saved. |
| May have | Posibilidad pasada (incierta) | Someone may have stolen the jewels. | The jewels may have been stolen. |
| Might have | Posibilidad remota en el pasado | She might have left the door open. | The door might have been left open. |
| Must have | Deducción / certeza en el pasado | Someone must have taken my keys. | My keys must have been taken. |
| Should have | Consejo no seguido / crítica | You should have told me the truth. | The truth should have been told. |
| Would have | Condicional pasado no cumplido | They would have cancelled the event. | The event would have been cancelled. |
⚠️ Diferencia clave: The work must be done (ahora o en el futuro) vs The work must have been done (deduzco que ya se hizo en el pasado). El «have been» es la marca inequívoca de que hablamos de un tiempo pasado.
📝 Ejemplos detallados por contexto
🔹 Obligación y necesidad (must, have to, need to)
- All passengers must be seated before takeoff. (Normativa)
- The application has to be submitted by Friday. (Obligación externa)
- The grass needs to be cut. (Necesidad)
- These rules must have been ignored. (Deducción pasada)
🔹 Posibilidad y capacidad (can, could, may, might)
- This door can be opened with this key. (Capacidad)
- The situation could be improved. (Posibilidad)
- Your order may be delayed due to weather. (Posibilidad formal)
- His decision might be influenced by others. (Posibilidad remota)
- The package could have been lost in transit. (Posibilidad pasada)
🔹 Consejo y recomendación (should)
- Smoking should be banned in public places. (Recomendación)
- The children should be told the truth. (Consejo)
- The report should have been finished yesterday. (Crítica sobre el pasado)
🔹 Condicional (would)
- If I had more time, the work would be done. (Condicional presente)
- The party would have been enjoyed by everyone. (Condicional pasado)
🧪 5 Ejercicios prácticos con verbos modales en pasiva
Ejercicio 1: Transforma a pasiva (modales en presente/futuro)
- You must write the report today. → ________________________________
- Someone can fix the computer. → ________________________________
- You should take this medicine twice a day. → ________________________________
- They may cancel the event. → ________________________________
- You need to water the plants. → ________________________________
✅ Ver solución
- The report must be written today.
- The computer can be fixed.
- This medicine should be taken twice a day.
- The event may be cancelled.
- The plants need to be watered.
Ejercicio 2: Transforma a pasiva (modales en pasado)
- Someone must have stolen the painting. → ________________________________
- You should have told her the truth. → ________________________________
- They could have rescued the hikers. → ________________________________
- Someone might have left the door open. → ________________________________
- The company would have launched the product. → ________________________________
✅ Ver solución
- The painting must have been stolen.
- The truth should have been told to her.
- The hikers could have been rescued.
- The door might have been left open.
- The product would have been launched.
Ejercicio 3: Completa con la forma pasiva correcta del modal (presente)
- All the documents __________ (must / sign) before leaving.
- This problem __________ (can / solve) easily.
- The invitations __________ (should / send) as soon as possible.
- Smoking __________ (may / prohibit) in this area.
- The car __________ (need / wash). It’s very dirty.
✅ Ver solución
- must be signed
- can be solved
- should be sent
- may be prohibited
- needs to be washed
Ejercicio 4: Completa con la forma pasiva correcta del modal (pasado)
- The treasure __________ (might / hide) somewhere in this cave.
- Your purse __________ (could / steal) while you were shopping.
- The game __________ (should / play) differently.
- He __________ (must / leave) behind by accident.
- The old bridge __________ (would / destroy) by the flood.
✅ Ver solución
- might have been hidden
- could have been stolen
- should have been played
- must have been left
- would have been destroyed
Ejercicio 5: Elige la opción correcta (modal pasiva presente o pasado)
- The package __________ by now, but we haven’t received it.
a) should be delivered / b) should have been delivered - All passengers __________ their seat belts before takeoff.
a) must be fastened / b) must fasten - This letter is urgent. It __________ immediately.
a) must be sent / b) must have been sent - The windows are open. They __________ by someone.
a) could be left / b) could have been left - This is a secret. It __________ to anyone.
a) must not be told / b) must not have been told
✅ Ver solución
- b) should have been delivered (la acción esperada es pasada)
- b) must fasten (activa; aquí el sujeto realiza la acción)
- a) must be sent (acción futura inmediata, no pasada)
- b) could have been left (posibilidad en el pasado)
- a) must not be told (prohibición para el futuro)
📚 Sigue practicando la voz pasiva
- La voz pasiva en inglés: qué es y cuándo usarla – Fundamentos.
- Cómo formar la pasiva en todos los tiempos verbales – Tablas completas.
- La pasiva con verbos modales en inglés – ¡Estás aquí!
- Pasiva de doble objeto: give, send, show – Dos formas de construir la pasiva.
- Ejercicios de voz pasiva en inglés resueltos – Práctica intensiva.



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