subject + modal + be + past participle (+ by + doer)After the modal, use be. Then use the past participle. Add by + doer only when that information matters.
Passive with Modals
B1Use passive with modals as modal + be + past participle: It must be done. The action or result matters more than the doer.
What you'll learn
- Build passive forms with can, must, should, may, and might.
- Choose passive when the doer is unknown or not important.
- Add by + doer only when that detail matters.
- Recognize modals that often appear in passive rules and instructions.
Structure
Build a sentence
Modal
Subject
Past participle
The reportmustbefinished
The report must be finished today.
Use modal + be + past participle.
When to use
Rules and instructions
Use this form for rules, notices, and procedures. The action matters more than the person who does it: Seat belts must be worn.
Focus on the result
Use the passive when you want attention on what happens to something: The files can be shared online.
Unknown doer
Use it when you do not know who does the action or do not need to say it: The problem might be caused by heat.
Markers
mustcanshouldmaymightcannot
Common mistakes
Wrong
The report must finished today.
Correct
The report must be finished today.
Passive with a modal always needs be after the modal.
Wrong
The door can be close at night.
Correct
The door can be closed at night.
After be in the passive, use the past participle, not the base verb.
Wrong
The song can be sung Maria.
Correct
The song can be sung by Maria.
Use by before the doer when you include the person or thing that does the action.
Wrong
Someone must clean these windows before noon.
Correct
These windows must be cleaned before noon.
When the doer is not important, passive keeps the focus on the thing affected.
Common misconceptions
❝ After a modal, I can use the past participle directly in the passive. ❞
Passive with modals needs be: can be seen, must be done, should be checked.
❝ Every passive sentence needs by + the doer. ❞
Many passive sentences do not need by because the doer is unknown, obvious, or not important.
Skills in this rule (4)
FORM_MODAL_BE_PAST_PARTICIPLEw5Build passive sentences with modal + be + past participle
Use a modal verb, then be, then the past participle when the action matters more than the person who does it. This pattern works with can, must, should, may, and similar modals.
CHOOSE_PASSIVE_WHEN_DOER_IS_UNKNOWNw4Choose the passive when the doer is unknown, obvious, or unimportant
Use the passive when you focus on the result, rule, or object affected by the action. The person who does the action can stay unstated.
ADD_BY_WHEN_DOER_MATTERSw3Add by + person or thing when the doer matters
Use by only when the listener needs to know who or what does the action. If that information adds nothing, leave it out.
MARKERS_RULES_POSSIBILITYw3Recognize modals that often appear in passive sentences
Words like must, can, should, may, and might often introduce rules, possibility, advice, or ability in the passive. They help you predict this pattern.