Unit 5: Active Passive Voice

I. Orientation

Voice is a grammatical system that shows the relationship between the subject, the verb, and the action in a clause. In the active voice, the subject performs the action; in the passive voice, the subject receives the action. The choice of voice changes emphasis, information flow, and style, but it does not normally change the basic event or its tense.

• Governing principle: Active voice follows the pattern subject + verb + object; passive voice usually follows object + form of be + past participle + by + performer.
• Action and receiver: The active subject is generally the performer or agent, while the passive subject is the receiver or affected person or thing.
• Transitive verbs: A passive sentence normally requires a transitive verb, because a transitive verb takes an object: The engineer repaired the bridge.
• Tense preservation: When changing voice, preserve the tense by changing the auxiliary verb, not the past participle: writes becomes is written; wrote becomes was written.
• Object movement: The active object normally becomes the passive subject: The committee approved the plan becomes The plan was approved by the committee.
• Agent omission: The performer may be omitted when it is unknown, obvious, unimportant, or deliberately withheld: The window was broken.
• Agreement: In passive constructions, the auxiliary agrees with the new subject: The letter was sent but The letters were sent.
• Meaning and emphasis: Voice is not merely a mechanical transformation; it helps speakers decide whether to foreground the actor, action, result, or receiver.

II. Active Voice and Passive Voice — Rules of active and passive voice

A. Definition and structural foundation

Active and passive voice are two ways of organizing the same basic action, although the change may also alter emphasis. The active form highlights the performer, while the passive form highlights the receiver or result.

• Active structure: The subject performs the action.

  Subject + verb + object
  The scientist conducted the experiment.

Here, the scientist is the subject, conducted is the verb, and the experiment is the object.

• Passive structure: The object of the active sentence becomes the subject of the passive sentence.

  Object + be + past participle + (by + subject)
  The experiment was conducted by the scientist.

Was preserves the past tense, and conducted is the past participle.

• Core transformation: Identify the active object, move it to subject position, use the correct form of be, change the main verb to its past participle, and add the agent with by if necessary.
• Meaning relationship: The manager signed the contract and The contract was signed by the manager describe the same signing event, but the first emphasizes the manager and the second emphasizes the contract.

B. Rules of active and passive voice

The rules of voice conversion depend mainly on the verb’s tense, the presence of an object, and the sentence type.

• Present simple: Use am/is/are + past participle.

  Active:  The company produces solar panels.
  Passive: Solar panels are produced by the company.

Produces becomes are produced because solar panels is plural.

• Past simple: Use was/were + past participle.

  Active:  The storm damaged several buildings.
  Passive: Several buildings were damaged by the storm.

Damaged becomes were damaged because the new subject is plural.

• Present continuous: Use am/is/are being + past participle.

  Active:  Workers are repairing the road.
  Passive: The road is being repaired by workers.

The progressive meaning is retained through is being repaired.

• Past continuous: Use was/were being + past participle.

  Active:  The team was testing the machine.
  Passive: The machine was being tested by the team.

• Present perfect: Use has/have been + past participle.

  Active:  The laboratory has completed the analysis.
  Passive: The analysis has been completed by the laboratory.

• Past perfect: Use had been + past participle.

  Active:  The workers had installed the equipment.
  Passive: The equipment had been installed by the workers.

• Future with will: Use will be + past participle.

  Active:  The council will announce the results.
  Passive: The results will be announced by the council.

• Modal verbs: Use modal + be + past participle.

  Active:  Students must submit the form.
  Passive: The form must be submitted by students.

Modals include can, could, may, might, shall, should, must, and ought to.

• Modal perfect forms: Use modal + have been + past participle.

  Active:  The team should have finished the task.
  Passive: The task should have been finished by the team.

• Negative sentences: Place not after the first auxiliary.

  Active:  The company did not deliver the goods.
  Passive: The goods were not delivered by the company.

• Questions: Move the auxiliary before the passive subject.

  Active:  Did the technician repair the device?
  Passive: Was the device repaired by the technician?

• Imperatives: Commands can use let + object + be + past participle, although ordinary active commands are often more natural.

  Active:  Close the door.
  Passive: Let the door be closed.

• Verbs without objects: Intransitive verbs such as sleep, arrive, and disappear generally cannot form ordinary passives because they have no object to move: The guests arrived has no standard passive form.
• Two objects: Verbs such as give, send, and offer may produce two passive patterns.

  Active:  The teacher gave the students an assignment.
  Passive: The students were given an assignment.
  Passive: An assignment was given to the students.

• Prepositional verbs: Keep the necessary preposition.

  Active:  The committee looked into the complaint.
  Passive: The complaint was looked into by the committee.

• Pronoun changes: Change object pronouns into subject pronouns after movement: They invited him becomes He was invited by them. The forms change as follows: me → I, him → he, her → she, us → we, them → they.

C. Usage of active and passive voice

The choice between voices should reflect the speaker’s communicative purpose. Active voice is usually direct and economical; passive voice is useful when the receiver, process, or result deserves greater attention.

• Active voice for clear agency: Use active voice when the performer matters.

  The safety officer inspected the laboratory.

The sentence immediately identifies who carried out the inspection.

• Active voice for directness: Active clauses normally use fewer words and make responsibility easier to identify: The department rejected the proposal is more direct than The proposal was rejected by the department.

• Active voice for instructions and reports: Directions are clearer when the responsible person or group is explicit: Attach the receipt to the application identifies the required action efficiently.

• Active voice for accountability: In workplace communication, The supplier delayed the shipment clearly assigns responsibility; the passive alternative, The shipment was delayed, may conceal the agent.

• Passive voice when the receiver is important: Use passive voice when the affected object is the topic.

  The bridge was opened in 1998.

The bridge, rather than the officials who opened it, is the central subject.

• Passive voice when the agent is unknown: My bicycle was stolen is appropriate when the thief is not known.
• Passive voice when the agent is obvious: The suspect was arrested does not need by the police, because the likely agent is understood.
• Passive voice in scientific and technical writing: Passive forms can emphasize procedures and findings: The samples were heated to 80°C. The procedure matters more than the unnamed technician.
• Passive voice in formal institutional writing: Administrative statements often foreground decisions or requirements: Applications must be submitted by Friday. The instruction is more important than the individual who imposes it.
• Passive voice for tact and diplomacy: A passive construction can avoid direct blame: A mistake was made in the report sounds less confrontational than You made a mistake in the report.
• Passive voice for process description: It can present steps in logical order: The solution is filtered, heated, and transferred to a sealed container. Each stage becomes the focus of attention.
• Avoiding unnecessary passives: Excessive passive voice can make writing vague, lengthy, or bureaucratic. Compare The decision was made by the committee after a discussion with the more compact The committee made the decision after discussion.
• Avoiding agentless ambiguity: If the responsible person is important, include the agent. The figures were changed leaves responsibility unclear; The accountant changed the figures is more informative.
• Maintaining appropriate emphasis: Choose the voice according to the sentence’s information structure:
  • Known topic first: The report was submitted yesterday keeps the report as the topic.
  • New actor first: The research team submitted the report yesterday introduces the team as the important information.
• Voice and style: Good communication uses both voices strategically rather than treating one as universally correct. A paragraph may begin with an active actor-focused sentence and then use passive sentences to maintain focus on the same object.
• Worked comparison: Consider the two forms below.

  Active:  The engineers tested the new material under pressure.
  Passive: The new material was tested under pressure by the engineers.

The active sentence answers “Who tested it?” and emphasizes the engineers. The passive sentence answers “What happened to the material?” and emphasizes the new material. In technical writing, the passive may be preferable when the material is already the paragraph’s topic; in an incident report, the active may be preferable when the engineers’ responsibility is significant.

• Limitations of conversion: Not every active sentence can be passivized naturally. The child laughed has no object, and The box weighs five kilograms does not normally become a standard passive because five kilograms is a measurement complement rather than an object receiving an action.
• Final selection principle: Use active voice when clarity, energy, and responsibility are central; use passive voice when the receiver, process, result, unknown agent, or formal focus is central. Always preserve the intended tense and meaning while checking auxiliary agreement.