Voice tells you who is doing the action and what receives it. In the active voice the doer (subject) acts; in the passive voice the receiver of the action becomes the grammatical subject. CDS papers reward candidates who can flip a sentence quickly and correctly. This guide gives you the rules, tense tables and the traps that cost easy marks.
Why Voice Matters in CDS English
The CDS English paper (Paper II) regularly carries direct transformation items where you must change a given active sentence into the passive, or vice-versa. These are scoring questions because the answer follows fixed rules — there is rarely any ambiguity once you know the procedure. Unlike comprehension, where two options may look equally tempting, a voice question has exactly one correct form, so a candidate who has drilled the rules can answer in seconds and bank the mark with confidence.
Voice also feeds into spotting errors, sentence improvement and even comprehension, where the examiner tests whether you understand that ‘The committee approved the plan’ and ‘The plan was approved by the committee’ mean the same thing with a different emphasis. Official, scientific and journalistic writing leans heavily on the passive, so the topic is also useful for the interview and essay stages of selection, where a varied sentence structure marks out a polished officer-like candidate.
Over the last decade, examiners have favoured continuous and perfect tenses, modal verbs and question forms in these items, precisely because they catch out candidates who only memorised the simple present and past. We will cover each of these systematically so that no pattern surprises you in the hall.
Active voice stresses the doer; passive voice stresses the action or its receiver. Both are grammatically correct — the exam tests transformation, not which is ‘better’.
Active and Passive: The Core Idea
A verb is in the active voice when its subject performs the action. It is in the passive voice when its subject receives the action. The change is not about meaning — the event is identical — but about which noun we choose to put in the spotlight at the start of the sentence.
- Active: Rahul wrote the essay. (subject Rahul does the writing)
- Passive: The essay was written by Rahul. (subject essay receives the action)
Notice three changes: the object (essay) moves to the front, the verb becomes ‘be + past participle’ (was written), and the original subject moves after by. Every passive sentence you ever build, however long or complex, is just a careful application of these three moves.
It helps to remember the three building blocks of a simple statement: the subject (the doer), the verb (the action) and the object (the receiver). In the active voice the order is Subject–Verb–Object. In the passive voice that order is reversed so that the object leads and the doer, if mentioned at all, trails behind ‘by’. Train your eye to spot these three parts instantly, because the whole transformation depends on locating the object correctly.
Passive structure = Object + correct form of ‘be’ + V3 (past participle) + by + Subject. Only verbs that take an object (transitive verbs) can be made passive.
The Three-Step Conversion Method
Use this reliable routine for every active-to-passive question. With a little practice it becomes automatic, and you will be able to run through all three steps mentally before you even look at the options.
- Find the object of the active sentence and make it the new subject. If a pronoun is the object, change it to its subject form: me→I, him→he, her→she, them→they, us→we.
- Keep the tense the same, but write the verb as the matching form of ‘be’ + the past participle (V3). This is the heart of the transformation, so identify the tense of the active verb first.
- Move the old subject after by (drop it if it is unknown or unimportant), changing its pronoun to the object form: I→me, he→him, she→her, they→them, we→us.
A handy way to remember the swap is that the doer and the receiver simply exchange places and exchange pronoun forms. Whatever was the subject becomes the object of ‘by’, and whatever was the object steps up to become the new subject.
The tense of the passive is decided only by the form of ‘be’. The main verb is always the past participle (V3) and never changes its form, whatever the tense. So your first job is always to label the tense of the active sentence correctly.
Tense-wise Passive Forms
Memorise how ‘be’ changes across tenses. Take the simple sentence She writes a letter as the model.
Simple tenses
- Present: writes → is written — A letter is written by her.
- Past: wrote → was written — A letter was written by her.
- Future: will write → will be written — A letter will be written by her.
Continuous tenses
- Present: is writing → is being written
- Past: was writing → was being written
Perfect tenses
- Present: has written → has been written
- Past: had written → had been written
- Future: will have written → will have been written
Read each table aloud a few times until the pattern of ‘be’ becomes second nature: is/was/will be for simple tenses, is being/was being for continuous tenses, and has been/had been/will have been for perfect tenses. Once you can produce the right form of ‘be’ on demand, attaching the past participle is the easy part.
Future continuous and perfect continuous tenses are not normally used in the passive. Avoid forms like ‘will be being written’ — the exam will never expect them. If you ever feel tempted to stack ‘be being’ after ‘will’, stop: the sentence almost certainly does not need the passive at all.
Passive with Modals
Modal verbs (can, could, may, might, must, should, ought to, have to) keep the modal and add be + V3.
- You must finish the work. → The work must be finished (by you).
- We can solve this sum. → This sum can be solved (by us).
- One should respect elders. → Elders should be respected.
- They may postpone the match. → The match may be postponed.
- You ought to obey the rules. → The rules ought to be obeyed.
Semi-modals such as have to, has to, had to, is going to behave the same way: ‘He has to submit the form’ becomes ‘The form has to be submitted by him’. The trick is simply to slot ‘be + V3’ in after whatever modal expression carries the meaning.
Modal passive = modal + be + past participle. The modal itself never changes; only ‘be + V3’ follows it.
Passive of Imperative Sentences
Commands and requests (imperatives) form the passive with Let or with You are requested/advised to…
- Open the door. → Let the door be opened.
- Do not waste time. → Let time not be wasted.
- Please help me. → You are requested to help me.
- Work hard. → You are advised to work hard.
- Shut the windows. → Let the windows be shut.
The reason imperatives behave differently is that they have no visible subject — the ‘you’ is understood rather than stated. Because there is no doer to move after ‘by’, English supplies the structure ‘Let + object + be + V3’ for orders, and the polite frame ‘You are requested/advised to…’ for requests and advice. Decide first whether the sentence is a command or a request, and the correct frame follows automatically.
For a plain order, use ‘Let + object + be + V3’. For polite requests (please, kindly) use ‘You are requested/advised to…’.
Passive of Questions
Questions keep their question form after transformation.
Yes/No questions
- Did he break the cup? → Was the cup broken by him?
- Has she finished the task? → Has the task been finished by her?
Wh- questions
- Who wrote this novel? → By whom was this novel written?
- What did you buy? → What was bought by you?
- Why did they reject the plan? → Why was the plan rejected by them?
The golden rule with questions is that the sentence must stay a question: the auxiliary verb still comes before the subject, and the question word stays at the front. In Yes/No questions the auxiliary of the active sentence (did, has, will, is) tells you the tense, and you rebuild it with the right form of ‘be’. In Wh- questions, keep the question word in place unless it is the doer, in which case it becomes ‘By whom’.
‘Who’ as the doer becomes By whom in the passive, not ‘Who’. Many candidates wrongly keep ‘Who was…’. Equally, do not turn the question into a statement by writing ‘The novel was written by whom’ — the verb must still lead.
When to Drop or Change the Agent
The ‘by + doer’ phrase (the agent) is often left out when the doer is obvious, unknown or unimportant.
- Someone has stolen my bag. → My bag has been stolen. (agent unknown → dropped)
- They speak English here. → English is spoken here. (general ‘they’ → dropped)
- People believe that he is honest. → It is believed that he is honest.
That last pattern — starting with the introductory ‘It is said/believed/reported that…’ — is a favourite of examiners for sentences that begin with vague subjects like people, everybody, one or they. Learn it as a ready-made template.
Some passives use prepositions other than ‘by’, and the exam likes to test these because candidates reflexively write ‘by’:
- known to, satisfied with, surprised at, filled with, composed of, acquainted with, tired of.
For example, ‘Everyone knows him’ becomes ‘He is known to everyone’, not ‘by everyone’. Keep a short list of these special prepositions in your revision notes.
Pronoun forms change with role: I→me, we→us, he→him, she→her, they→them after ‘by’. Write ‘by me’, never ‘by I’.
Worked Example
Convert into the passive voice: The teacher had explained the lesson before the bell rang.
Apply the three-step method to the main clause.
The time clause ‘before the bell rang’ has no object, so it stays unchanged. This illustrates an important habit: in a sentence with more than one clause, transform only the clause that actually has an object, and leave intransitive or subordinate parts exactly as they are. Rushing to passivise the whole sentence is a frequent cause of wrong answers.
Sentences with Two Objects
Verbs like give, offer, teach, tell, pay, send can take two objects. Either object can become the passive subject; usually the person is chosen.
- Active: The principal gave him a prize.
- Passive (person first): He was given a prize by the principal.
- Passive (thing first): A prize was given to him by the principal.
Both passive versions are grammatically acceptable, but examiners usually present the person-first version as the key, because it reads more naturally. When the indirect object (the person) is promoted to subject, the direct object (the thing) simply follows the verb. When instead the thing is promoted, the person needs the preposition to in front of it. Watch a couple more pairs:
- The manager offered me a job. → I was offered a job by the manager. / A job was offered to me by the manager.
- She taught the children grammar. → The children were taught grammar by her.
When the thing becomes the subject, insert to before the person: ‘A prize was given to him’. Forgetting this preposition is a frequent slip.
Previous-Year Style Question
Q. Change the following into the passive voice: ‘The committee is considering your application.’
(a) Your application is considered by the committee.
(b) Your application was being considered by the committee.
(c) Your application is being considered by the committee.
(d) Your application has been considered by the committee.
Answer: (c). The active verb ‘is considering’ is present continuous, whose passive form is ‘is being + V3’. So the correct passive is ‘Your application is being considered by the committee.’ Options (a), (b) and (d) use the wrong tense of ‘be’.
Quick Revision
- Passive = Object + correct ‘be’ + past participle (V3) + by + Subject.
- Only transitive verbs (those with an object) can be made passive.
- Tense is fixed by the form of ‘be’; the main verb is always V3.
- Modals: modal + be + V3. Imperatives: Let + object + be + V3.
- Questions stay questions; ‘Who’ → ‘By whom’.
- Drop the agent when it is unknown or unimportant; mind ‘by me/him/her’.
Frequently asked questions
How do I quickly identify if a sentence can be made passive?
Check whether the verb has a direct object (someone or something receiving the action). Transitive verbs like 'write', 'eat' and 'build' can be made passive; intransitive verbs like 'sleep', 'arrive' and 'die' cannot.
Does the tense change when I convert active to passive?
No. The tense stays exactly the same. Only the form of the verb 'be' reflects that tense, while the main verb is always written as the past participle (V3).
When should I leave out the 'by + doer' part?
Drop the agent when the doer is unknown, obvious or unimportant, for example 'My purse was stolen' or 'English is spoken here'. Keep it only when the doer carries useful information.
How is the passive of a 'Who' question formed?
Replace 'Who' (the doer) with 'By whom'. For example, 'Who painted this?' becomes 'By whom was this painted?' The verb follows the 'be + V3' rule of the original tense.
How important is voice transformation for the CDS exam?
It is a high-value, rule-based topic. Voice change questions appear regularly in the CDS English paper and, because the answers follow fixed patterns, they are among the easiest marks to secure with practice.
Related CDS / OTA English topics
Want a teacher to walk you through CDS / OTA English?
Cavalier's CDS / OTA batches break every topic into classroom sessions with daily practice, tests and doubt-clearing.