Spanish Passive Sentences with Modals: Can, Must, and Should
Learn to combine ser + past participle with modal verbs like poder, deber, and tener que to say what can, must, or should be done in Latin American Spanish.
By TheaFirst conversations · Yapr Learn
In Spanish, you can express ideas like 'The form must be signed' or 'This can be done tomorrow' by combining a modal verb with the passive construction ser + past participle. The modal comes first and is conjugated; ser stays in the infinitive, and the past participle agrees in gender and number with the subject. This lesson focuses on poder, deber, and tener que in passive sentences, using broadly useful Latin American Spanish.
By the end, you can…
- form passive sentences with poder, deber, and tener que plus ser + past participle.
- make the past participle agree in gender and number with the subject.
- distinguish between obligation, recommendation, and possibility in passive sentences.
Listen once. Try it slowly. Then say it without looking.
Checking available voices…
El formulario debe ser firmado.
The form must be signed.
el for-mu-LA-rio DE-be ser fir-MA-do
Debe ser + participle expresses strong obligation or requirement. Common in instructions and official contexts.
La solicitud puede ser enviada por correo electrónico.
The application can be sent by email.
la so-li-si-TUD PWE-de ser en-via-da por ko-RRE-o e-lek-TRO-ni-ko
Puede ser + participle expresses possibility or permission. The participle enviada agrees with solicitud (feminine).
Las facturas deben ser pagadas antes del viernes.
The invoices must be paid before Friday.
las fak-TU-ras DE-ben ser pa-GA-das AN-tes del BYER-nes
Deben is plural to match las facturas; pagadas is feminine plural. Use for deadlines and rules.
Este documento tiene que ser revisado por un abogado.
This document has to be reviewed by a lawyer.
ES-te do-ku-MEN-to TYE-ne ke ser re-vi-SA-do por un a-bo-GA-do
Tiene que ser + participle expresses practical necessity, often stronger or more immediate than debe ser.
Los resultados deberían ser publicados mañana.
The results should be published tomorrow.
los re-sul-TA-dos de-be-RI-an ser pu-bli-KA-dos ma-NA-na
Deberían is the conditional form, used for recommendations or expectations rather than strict obligations.
Pronunciation guides are approximate. Slow playback keeps the original pitch.
Make it make sense
Useful pattern
The structure is modal + ser + past participle. Conjugate the modal for the subject, keep ser in the infinitive, and make the participle agree with the subject. Examples: El informe debe ser entregado. (The report must be handed in.) Las cartas pueden ser firmadas aquí. (The letters can be signed here.) Los documentos tienen que ser traducidos. (The documents have to be translated.) Notice that the participle changes: entregado, firmadas, traducidos.
When to use it
Use debe ser for rules and formal requirements: La puerta debe ser cerrada a las diez. Use puede ser for possibility or permission: La cita puede ser cambiada. Use tiene que ser for practical necessity: El pago tiene que ser hecho hoy. Use debería ser for recommendations: El texto debería ser más claro. In Latin American Spanish, these forms appear in signs, instructions, emails, and everyday advice. The agent, if mentioned, is introduced with por: La carta fue escrita por Ana.
Listen to each line, then take one part and reply out loud.
¿Ya sabes qué hay que hacer con la solicitud?
Do you already know what has to be done with the application?ya SA-bes ke AI ke a-SER kon la so-li-si-TUDSí, la solicitud debe ser firmada por el director.
Yes, the application must be signed by the director.si la so-li-si-TUD DE-be ser fir-MA-da por el di-rek-TOR¿Y los documentos adjuntos pueden ser enviados por correo?
And can the attached documents be sent by mail?i los do-ku-MEN-tos ad-JUN-tos PWE-den ser en-via-dos por ko-RRE-oSí, pero deberían ser revisados antes de enviarlos.
Yes, but they should be reviewed before sending them.si PE-ro de-be-RI-an ser re-vi-SA-dos AN-tes de en-viaR-losA little context goes a long way
In Latin American Spanish, debe ser and tiene que ser are common in formal notices and workplace communication, while debería ser softens advice. In casual speech, speakers often prefer active sentences with se, such as Se debe firmar el formulario, so the passive with ser may sound more formal or written.
One thing to watch for
El formulario debe ser firmar.
Try this instead: Use the past participle, not the infinitive, after ser. Correct: El formulario debe ser firmado. The participle firmado agrees with the masculine singular subject formulario.
Your turn
Try answering out loud before checking a possible answer.
1Translate: 'The reports can be printed here.'
Show a sample answer
Los informes pueden ser impresos aquí.
Pueden agrees with los informes, and impresos is masculine plural. Imprimir has the irregular participle impreso; the regularized form imprimido is also accepted in modern usage, but impresos is the more common standard form.
2Translate: 'The house must be cleaned before the party.'
Show a sample answer
La casa debe ser limpiada antes de la fiesta.
Debe is singular to match la casa, and limpiada is feminine singular. Tiene que ser limpiada is also correct and slightly more emphatic.
3Translate: 'The invitations should be sent today.'
Show a sample answer
Las invitaciones deberían ser enviadas hoy.
Deberían is the conditional plural for recommendations, and enviadas agrees with las invitaciones. Deben ser enviadas is also possible but sounds more like a strict obligation.
To say what can, must, or should be done in Spanish, use a conjugated modal (puede, debe, tiene que, debería) + ser + a past participle that agrees with the subject.
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