NDA (National Defence Academy) · English Language & Comprehension
Active & Passive Voice
Converting sentences between active and passive voice while preserving meaning and tense.
Active voice names the doer as subject; passive puts the receiver first and builds the verb as a form of be plus the past participle. Every conversion question on this topic is the same three decisions: find the object, keep the tense on be, and rewrite — or refuse the rewrite when there is no object.
- NDA (National Defence Academy)
- Medium level
- 8 concepts
- 5 practice questions
1Object becomes subject; verb becomes be + V3
In the passive, the object of the active sentence becomes the subject, and the verb is rebuilt as a form of be plus the past participle (V3). Active: The chef cooks the meal. Passive: The meal is cooked by the chef. Meaning and tense stay put; only the packing of the sentence changes.
The doer moves into a by-phrase and is often optional later. What is never optional is the past participle: cooks becomes cooked, not cooking or cook. If the new subject is not the old object, the sentence is not a voice change — it is a different claim.
Figure. Object becomes subject; verb rebuilds as be + past participle.
How it works
- Find the objectUnderline the receiver of the action — that noun phrase will be the new subject.
- Build be + V3Choose the be form that matches the active tense, then attach the past participle of the main verb.
- Park the doerMove the old subject into by + agent, or leave it off when the stem does not need it.
| Role | Active | Passive |
|---|---|---|
| Subject | doer (chef) | receiver (meal) |
| Verb | tensed main verb (cooks) | be (same tense) + V3 (is cooked) |
| Object / agent | receiver as object | doer in optional by-phrase |
Choose the correct passive of: The chef cooks the meal.
- The meal is cooked by the chef.
- The meal is cooking by the chef.
- The chef is cooked by the meal.
The meal (old object) must become the subject, and cooks must become is cooked — be + past participle. Option B uses cooking (V-ing), not V3. Option C swaps roles so the chef is the patient, which changes the meaning instead of changing the voice.
2Tense rides on be, not on V3
The tense of the active verb is carried by the be form in the passive. V3 stays fixed; only be changes. Simple present uses is/am/are + V3; simple past uses was/were + V3; present continuous uses is/are being + V3; present perfect uses has/have been + V3.
The most common trap is shifting the tense while rewriting — writing was cooked for a present stem, or dropping being from a continuous passive. First name the active tense, then plug the matching be form before V3.
Figure. Tense lives on the be form; V3 does not change with tense.
How it works
- Name the tenseRead the active verb and say the tense aloud — simple present, past, continuous, perfect.
- Pick the be formLook up the matching be pack: is/am/are, was/were, is/are being, has/have been.
- Keep V3 fixedAttach the same past participle; do not invent a second tense marker on the main verb.
| Active tense | Passive verb pack | Example |
|---|---|---|
| Simple present | is/am/are + V3 | Letters are written |
| Simple past | was/were + V3 | The letter was written |
| Present continuous | is/are being + V3 | The letter is being written |
| Present perfect | has/have been + V3 | The work has been done |
| Past perfect | had been + V3 | The work had been done |
Change to passive: The committee has approved the proposal.
- The proposal has been approved by the committee.
- The proposal was approved by the committee.
- The proposal has approved by the committee.
Has approved is present perfect, so the passive needs has/have been + V3: has been approved. Option B drops to simple past (was approved) — a tense-shift error. Option C keeps has but drops been, so the participle has no passive be pack.
3Only a transitive verb can passivise
A verb needs an object before it can be made passive. She sleeps has no object, so no receiver can become subject. She reads a book can become A book is read by her. If you cannot name what receives the action, stop — passive is impossible, not merely awkward.
Exam stems plant intransitive or objectless actives next to tidy passive options. The trap is polishing the verb form when the real answer is that the sentence cannot be converted.
Figure. Only a verb with an object can become passive.
How it works
- Ask for the objectAfter the verb, is there a noun phrase that receives the action?
- Refuse if noneNo object means no passive — do not invent a subject from a complement or adverbial.
- Convert if presentPromote that object and build be + V3 as usual.
| Active | Object? | Passive? |
|---|---|---|
| She reads a book | a book | A book is read by her |
| They built the bridge | the bridge | The bridge was built by them |
| She sleeps | none | impossible |
| The sun rises | none | impossible |
| He arrived at noon | none (at noon is adverbial) | impossible |
Which sentence can be turned into a correct passive?
- She reads a book.
- She sleeps soundly.
- The guests arrived early.
Reads takes the object a book, so A book is read by her is available. Sleeps and arrived are intransitive here — soundly and early are adverbials, not objects — so neither has a receiver to promote.
4Modals keep the modal and add be + V3
With a modal, the modal stays and the main verb becomes be + V3: You can solve it → It can be solved (by you). Must, should, may, might, will, would follow the same pack — modal + be + V3 — never modal + V3 alone and never a tensed be that replaces the modal.
The agent by-phrase is still optional. What fails on paper is dropping be (It can solved) or finite-ising the modal away (It is solved can by you).
Figure. Keep the modal; rebuild the main verb as be + V3.
How it works
- Keep the modalLeave can/must/should/will where it is; do not turn it into is or was.
- Insert be + V3After the modal, write be and the past participle of the main verb.
- Promote the objectMake the old object the subject; park the doer in by if needed.
| Active | Passive pack | Passive |
|---|---|---|
| You can solve it | can be + V3 | It can be solved |
| She must finish the work | must be + V3 | The work must be finished |
| They should open the gate | should be + V3 | The gate should be opened |
| He will send the mail | will be + V3 | The mail will be sent |
Choose the correct passive of: You must complete the task today.
- The task must be completed today.
- The task must completed today.
- The task is must completed today.
Must stays, then be + V3: must be completed. Option B drops be. Option C inserts a finite is and strands must, which is not an English verb pack.
5Imperatives become Let + object + be + V3
A command has no stated subject, so its passive cannot start with a promoted doer. Use Let + object + be + V3: Open the door → Let the door be opened. Shut the door → Let the door be shut.
Do not write The door is opened as the exam passive of an imperative stem when the stem is a bare command — that form is a simple-present passive of a different active (Someone opens the door), not the standard imperative conversion the papers mark.
Figure. Commands become Let + object + be + V3 — no stated doer to promote.
How it works
- Spot the commandBare verb at the start, no subject — Open…, Shut…, Complete…
- Name the objectFind what is acted on; that noun phrase follows Let.
- Write Let … be + V3Let + object + be + past participle. Keep the same object; do not invent a subject they.
Change to passive: Shut the door.
- Let the door be shut.
- The door is shut.
- Let the door shut.
Imperatives take Let + object + be + V3, so Let the door be shut. Option B is a simple-present/stative passive of a different active, not the command template. Option C drops be, leaving shut as a bare verb after door.
6Pronouns swap case when they swap roles
When a pronoun moves from subject to agent, or from object to subject, its case must change with the role: I ↔ me, he ↔ him, she ↔ her, we ↔ us, they ↔ them. Active: She helped me. Passive: I was helped by her — not Me was helped by she.
A perfect be + V3 still fails if the pronouns keep their old forms. Check case after you finish the verb pack; the stem is built to punish the half-rewritten sentence.
Figure. When pronouns swap roles, case must swap with them.
How it works
- Rewrite the verbBuild the passive verb pack first so tense is safe.
- Promote the object pronounObject form becomes subject form: me → I, him → he, her → she, us → we, them → they.
- Demote the subject pronounOld subject becomes by + object form: she → by her, he → by him, I → by me.
| Subject form | Object form | Active → Passive cue |
|---|---|---|
| I | me | I helped her → She was helped by me |
| he | him | He called us → We were called by him |
| she | her | She helped me → I was helped by her |
| we | us | We told them → They were told by us |
| they | them | They invited me → I was invited by them |
Choose the correct passive of: She helped me.
- I was helped by her.
- Me was helped by she.
- I was helped by she.
Me must become subject I, and she must become object her in the by-phrase. Option B keeps both pronouns in the wrong case. Option C fixes the subject but leaves she after by.
7The by-agent is optional when the doer is empty
By + agent is grammatical, not mandatory. Drop it when the doer is unknown, obvious, or unimportant: The bridge was built in 1920. Keep it when the stem is testing who did the action, or when omitting it would leave the sentence incomplete for the question asked.
A common wrong move is inventing a vague they/someone in the active when the passive had no agent — or, on the way back to active, forcing by someone into every passive. Voice conversion preserves information; it does not require manufacturing a doer the original never named.
Figure. Drop by-agent when the doer is empty or unimportant; keep it when tested.
How it works
- Finish the verb packPromote the object and write be + V3 before worrying about by.
- Ask who mattersIs the doer named in the active, and does the question need that name?
- Keep or drop byKeep by + agent when the doer is given and relevant; drop it when the doer is unknown or unimportant.
Which is the best passive if the doer is unimportant: They built the bridge in 1920.
- The bridge was built in 1920.
- The bridge was built by them in 1920.
- The bridge built in 1920.
With an unimportant they, the clean passive drops the agent: The bridge was built in 1920. Option B is grammatical but keeps a hollow agent the stem called unimportant. Option C drops be, so built is not a passive verb pack.
8Prefer passive when the receiver should lead
Passive is not a decoration for formal tone. Use it when the receiver is the news, when the doer is unknown, or when a series of sentences should keep the same subject for flow. Prefer active when the doer is the point of the sentence and is already known.
Exam improvement items punish a passive that hides a needed agent, and punish an active that forces a dummy they into a sentence whose focus is the object. Choose voice for focus, not for length.
Figure. Choose passive when the receiver is the news or the doer is empty — not for tone alone.
How it works
- Name the newsWhich noun phrase should the reader meet first — doer or receiver?
- Check the doerUnknown, obvious, or irrelevant → passive without by is usually cleaner.
- Pick voiceLead with the receiver → passive. Lead with a named, important doer → active.
| Situation | Prefer | Why |
|---|---|---|
| Doer unknown | Passive, no by | My wallet was stolen |
| Receiver is the topic | Passive | The treaty was signed in 1947 |
| Doer is the point | Active | Gandhi led the movement |
| Process / result focus | Passive | The samples were heated to 80 °C |
Which sentence best keeps focus on the bridge (doer unimportant)?
- The bridge was completed in 1920.
- They completed the bridge in 1920.
- Someone completed the bridge in 1920.
The bridge is the news and the doer is empty, so passive without agent leads correctly. Options B and C force a hollow they/someone into subject position and steal the focus the stem asked to keep on the bridge.
Notes
- Basic Transformation: In the passive voice, the object of the active sentence becomes the subject, and a form of 'be' + past participle (V3) is used. Active: 'The chef cooks the meal.' Passive: 'The meal is cooked by the chef.' The doer moves to a 'by' phrase (often optional).
- Tense is Preserved: The tense of the active verb is carried by the 'be' verb in the passive. Simple present → is/am/are + V3; simple past → was/were + V3; present continuous → is/are being + V3; present perfect → has/have been + V3.
- Only Transitive Verbs Passivise: A verb needs an object to be made passive. 'She sleeps' (intransitive) has no object and cannot become passive; 'She reads a book' can → 'A book is read by her.'
- Modals and Imperatives: Modals keep the modal + be + V3: 'You can solve it' → 'It can be solved (by you).' Imperatives become 'Let + object + be + V3': 'Open the door' → 'Let the door be opened.'
- Pronoun Shift: Subject and object pronouns swap forms when they change roles: I↔me, he↔him, she↔her, we↔us, they↔them. Active: 'She helped me.' Passive: 'I was helped by her.'
Formulas
- General passive template: Object + [correct form of be in the same tense] + past participle (V3) + (by + agent).
- Simple present passive: is/am/are + V3 ('Letters are written').
- Simple past passive: was/were + V3 ('The letter was written').
- Perfect tense passive: has/have/had been + V3 ('The work has been done').
- Modal passive: modal + be + V3 ('The task must be completed').
- Imperative passive: Let + object + be + V3 ('Let the window be closed').
Exam traps & shortcuts
- First locate the active verb's tense, then plug the matching 'be' form before V3 — this prevents tense-shift errors, the most common trap.
- Confirm the verb is transitive (has an object) before attempting a passive; if there is no object, passive is impossible.
- Swap subject/object pronouns to their correct case (I→me, he→him) or the sentence will read wrong even if the verb form is right.
- The 'by + agent' can be dropped when the doer is unknown or unimportant ('The bridge was built in 1920').
Reference tables
Locate the active tense first, then plug the matching be form before V3. Continuous needs being; perfect needs been.
| Active cue | Passive pack | Watch for |
|---|---|---|
| V1 / V1-s (write / writes) | is/am/are + V3 | Agreement with the new subject |
| V2 (wrote) | was/were + V3 | was/were with new subject number |
| is/are V-ing | is/are being + V3 | Do not drop being |
| has/have V3 | has/have been + V3 | Do not write has + V3 alone |
| modal + V1 | modal + be + V3 | Keep the modal; insert be |
| Bare imperative | Let + object + be + V3 | Not a plain is + V3 rewrite |
Recap
Read only this the night before.
- Core pack
- Object → subject; verb → matching be + V3; doer → optional by-phrase.
- Tense
- Tense lives on be. Continuous needs being; perfect needs been. Name the active tense before you rewrite.
- Transitive only
- No object, no passive. Adverbials are not objects — she sleeps and he arrived early do not convert.
- Modals / commands
- Modal + be + V3. Imperative → Let + object + be + V3.
- Pronouns
- Case follows role: She helped me → I was helped by her.
- Agent
- Drop by when the doer is unknown or unimportant. Do not invent they to fill an empty agent.
Practise Active & Passive Voice
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