Modal verbs and the passive combine very naturally. "You must send the form" becomes "The form must be sent." The modal keeps its meaning, and be plus the past participle replaces the active verb.
The pattern is modal plus be plus past participle for the present and future: can be done, should be checked, might be delayed. For the past, be changes to have been: must have been sent, could have been avoided.
This page covers the present and perfect modal passives, negatives, questions, and the by-agent. The 20-question drill explains the full pattern under each answer.
The rule
The basic pattern
- Form: modal plus be plus past participle: must be sent, can be seen, should be checked.
- The modal never changes, and the past participle does not change either.
- The meaning of the modal stays the same: ability, advice, obligation, possibility or permission.
- The agent moves behind by or disappears, exactly as in other passive sentences.
Common present modals
- Obligation: must be done, has to be done, should be finished.
- Ability and possibility: can be solved, could be improved, might be delayed.
- Permission: may be used, cannot be taken out of the room.
- Advice and expectation: should be checked, ought to be replaced.
Past modals in the passive
- Form: modal plus have been plus past participle: must have been sent.
- Use it for deductions and regrets about the past: "The parcel must have been delivered yesterday."
- Could have been avoids the passive of ability in the past: "The accident could have been avoided."
- Should have been done expresses a past criticism: "The report should have been checked."
Will, going to and other futures
- Will works directly with be: will be finished, will be sent.
- Going to be is common in speech: is going to be repaired.
- Have to keeps its own form in the passive: has to be cleaned, had to be paid.
- The passive of a future plan is very useful for announcements: "The results will be published on Monday."
Negatives, questions and the agent
- Add not after the modal: must not be touched, cannot be opened.
- Questions put the modal first: "Can the form be sent by email?"
- With have been, not goes after have: could not have been avoided.
- Add by plus the agent only when the doer matters: "The file must be signed by the manager."
Examples
- The form must be sent before Friday.Modal passive: must be plus the past participle sent.
- This door cannot be opened from the outside.A negative modal passive with can cannot.
- The problem can be solved in ten minutes.Can be plus the past participle expresses possibility.
- The parcel must have been delivered yesterday.Past deduction with must have been plus the participle.
- The accident could have been avoided.A past regret with could have been plus the participle.
- The report should have been checked before publication.Should have been criticises a missing past action.
- The results will be published on Monday.Will be plus the past participle forms the future passive.
- The roof is going to be repaired next week.Going to be plus the participle for a planned action.
- The room has to be cleaned every day.Have to keeps its own form before be.
- Can the application be sent by email?A modal passive question starts with the modal.
Common mistakes
- Wrong: The form must sent tomorrow. Right: The form must be sent tomorrow.
- A modal passive always includes be before the past participle.
- Wrong: The problem can be solve. Right: The problem can be solved.
- The passive uses the past participle solved, not the base form solve.
- Wrong: The report should have being checked. Right: The report should have been checked.
- The perfect passive uses have been plus the past participle, not being.
- Wrong: The results will been published. Right: The results will be published.
- Will takes the base form be. Been belongs after have or has.
- Wrong: The letter must be wrote by the manager. Right: The letter must be written by the manager.
- The passive needs the past participle written, not the past simple wrote.
Practice drill
Answer all 20 questions. Each answer is marked at once, and the rule is explained under the question.
The form ___ before Friday.
Show answer and explanation
Answer: A. must be sent The modal passive takes modal plus be plus past participle: must be sent.
This door ___ from the outside.
Show answer and explanation
Answer: B. cannot be opened A negative modal passive places not after the modal and keeps be plus the participle opened.
The problem ___ in ten minutes.
Show answer and explanation
Answer: C. can be solved Can be plus the past participle solved forms the present modal passive.
The parcel ___ yesterday.
Show answer and explanation
Answer: D. must have been delivered The past deduction takes must have been plus the past participle delivered.
The accident ___ if the driver had slowed down.
Show answer and explanation
Answer: A. could have been avoided A past regret in the passive takes could have been plus the participle avoided.
The report ___ before publication.
Show answer and explanation
Answer: B. should be checked Should be plus the past participle checked expresses present advice in the passive.
The results ___ on Monday.
Show answer and explanation
Answer: C. will be published The future passive takes will be plus the past participle published.
The roof ___ next week.
Show answer and explanation
Answer: D. is going to be repaired Going to be plus the past participle repaired forms the planned future passive.
The room ___ every day.
Show answer and explanation
Answer: A. has to be cleaned Have to keeps its form and is followed by be plus the past participle cleaned.
___ the application ___ by email?
Show answer and explanation
Answer: B. Can ... be sent A modal passive question starts with the modal, then subject, then be plus the participle sent.
The window ___ by the storm.
Show answer and explanation
Answer: C. might be damaged Might be plus the past participle damaged describes a possible passive event.
The application ___ online.
Show answer and explanation
Answer: D. may be submitted May be plus the past participle submitted gives permission in the passive.
The mistake ___ earlier.
Show answer and explanation
Answer: A. should have been noticed The past criticism takes should have been plus the past participle noticed.
The equipment ___ before use.
Show answer and explanation
Answer: B. must be checked Must be plus the past participle checked expresses obligation in the passive.
This medicine ___ by children.
Show answer and explanation
Answer: C. must not be taken A negative prohibition in the passive takes must not be plus the participle taken.
The painting ___ by a famous artist.
Show answer and explanation
Answer: D. might be painted Might be plus the past participle painted expresses possibility about the agent.
The tunnel ___ next year.
Show answer and explanation
Answer: A. could be completed Could be plus the past participle completed forms a future possibility in the passive.
The keys ___ in the kitchen.
Show answer and explanation
Answer: B. may be left May be plus the past participle left expresses present possibility in the passive.
The invoice ___ by the accountant.
Show answer and explanation
Answer: C. must be signed The by-agent follows the modal passive must be signed.
The road ___ last winter.
Show answer and explanation
Answer: D. should have been repaired Last winter makes the passive modal past: should have been repaired.
Drill complete
You answered every question.
Next topic: Past perfect vs past simple: which came firstTake the level test
Questions learners ask
How is a modal passive different from an ordinary passive?
The ordinary passive uses a form of be that carries the tense: is cleaned, was cleaned. A modal passive puts the modal in front of be, and the modal carries the meaning: must be cleaned, could be cleaned. The past participle stays the same.
When do I need have been instead of be?
Use have been when the modal looks back at a finished past possibility, deduction or regret: must have been sent, could have been avoided. Use plain be for present and future statements: must be sent, will be sent.
Can a modal passive take an agent with by?
Yes, when the doer matters: "The form must be signed by the manager." If the doer is unknown, obvious or unimportant, leave the agent out. The passive exists to let you skip it.
More grammar topics
Past perfect vs past simple: which came first
When one past event happens before another, the earlier event takes had plus the past participle. The later event stays in the past simple.
Phrasal verbs with look: after, for, forward to and more
Look keeps its basic idea of attention or eyes, and the particle decides what happens next: caring, searching, waiting, investigating or resembling.
Phrasal verbs with take: off, up, after and over
The particle decides whether take means removing clothes, leaving the ground, starting a hobby, resembling a parent or gaining control.
Take the free A1 to C2 level test to find your starting point.