Active-Passive voice Questions and Answers

Answer: D

The correct passive is This book must be read by everyone.

To turn an active sentence with a modal verb into the passive, keep the modal and add be + past participle: must read becomes must be read. The object this book becomes the subject, and everyone moves into the by phrase.

Should be read weakens the obligation to advice. Has to be read and is to be read express obligation in other words, but they change the modal, so they do not faithfully convert the original sentence.

Answer: A

The keyed answer is Who is feeding the child ?

By whom is the child fed? is a simple-present passive question. Its exact active form is Who feeds the child?, with whom becoming the subject who. That form is not among the options, and the key takes the only present-tense choice, Who is feeding the child?, as the closest.

The other options shift the tense further away: has fed is present perfect, was feeding is past continuous, and has been feeding is present perfect continuous. Their passives would be has been fed, was being fed and so on, not is fed.

Answer: B

The answer is is known: The efficiency of a plant is known by the load it can take.

The subject, the efficiency of a plant, does not know anything; it is what is judged. So the verb must be passive, and a general truth calls for the simple present: is known.

Knows and has known are active forms, which would make efficiency the knower. Has been known is passive but in the present perfect, which suits a state continuing up to now rather than a general rule.

Answer: C

The active form is The cat ate the fish.

'The fish was eaten by the cat' is in the simple past passive (was + past participle). In the active voice the agent 'the cat' becomes the subject and the verb returns to the simple past: ate.

'Had eaten' is the past perfect and 'eats' the simple present, so both change the tense. Since option C is correct, 'None of the above' is wrong.

Answer: A

The key gives Promises should be kept.

In a sentence with the indefinite subject one, the passive drops the agent altogether, because 'by one' adds nothing. The object becomes the subject, and the modal should is kept with be plus the past participle: 'should be kept'. Grammar books give the general statement in the plural, 'Promises should be kept'.

'One's promises should be kept by them' keeps an unnecessary agent and switches from one to them. 'Promises were kept' loses the modal and changes the tense. 'A promise should be kept' is also a passive of the same idea, but the key prefers the generic plural form that the standard rule produces.

Answer: C

The correct passive is By whom were you asked to draft this letter ?

In the active question Who asked you...? the subject is who and the verb is in the simple past. In the passive, who becomes by whom, the object you becomes the subject, and the verb becomes were asked, with question word order (auxiliary before subject).

Option A changes the tense to present, B uses who after a preposition and the present perfect, and D keeps statement word order (you were) in a question.

Answer: D

Correct answer: An exam will have been taken by the boys.

The future perfect will have taken becomes will have been taken. The options with would change the modal, and will had been puts a past auxiliary after will.

Answer: D

Correct answer: This work has to be finished by you as soon as you can.

Have to expresses obligation and becomes has to be + participle, singular to agree with this work. Has been finished reports it as already done, which the obligation contradicts.

Answer: B

Correct answer: The result has been announced by the school.

The present perfect has announced becomes has been announced. Has announced is still active, and has be and has being are not verb forms.

Answer: C

Correct answer: When she was seen by me, she was crossing the road.

Only the first clause goes passive: I saw her becomes she was seen by me. The second clause has no object and cannot be made passive, so it stays exactly as it is.