THE PASSIVE VOICE – THEORY
The passive of an active tense is formed by putting the verb to be into the same tense as the active verb and adding the past participle of the active verb. The object of an active sentence becomes the subject of the passive one:
Susan gave Tom a bunch of flowers. > Tom was given a bunch of flowers.
Auxiliary verbs + infinitives form the passive by using a passive infinitive:
You mustn’t smoke cigarettes here. > Cigarettes mustn’t be smoked here.
USES OF THE PASSIVE
when it is not necessary to mention the doer of the action:
The streets are swept every day.
when we don’t know or don’t remember who did the action:
The president was assassinated.
when the subject of an active verb is indefinite or unclear, like: one, you, people.
This sort of advertisement is seen everywhere.
when we are more interested in the action itself than in who performed it.
The new opera building is being built.
Sometimes we use the passive for psychological reasons:
We are going to reform the education system in Poland.
The taxes will have to be raised.
If we have a combination of verb + preposition in the active, the preposition stays with the verb in the passive:
He looked at me. > I was looked at.
Someone is looking after the children > The children are being looked after.
With verbs of reporting, such as: acknowledge, assume, believe, claim, consider, think, say etc. we might have two possible forms, but the form preferred in written English is the one employing the prefect infinitive:
People think he is a fool. > He is thought to be a fool.
People thought he was a fool. > He was thought to be a fool.
People think he was a fool. > He is thought to have been a fool.
People thought he had been a fool. > He was thought to have been a fool.
have + object + past participle:
I had my car washed yesterday.
I had my car stolen.
Infinitives placed after passive verbs are usually full infinitives:
I heard her say it. > She was heard to say it.
The teacher has made us work hard. > We were made to work hard.