A sentence can be written in two different ways to show whether the subject performs an action (active voice) or receives the action (passive voice). Most sentences are written in the active voice. Why passive sentences are sometimes preferred is explained in Part 4.
Active and passive sentences
The verb or verb phrase used in the passive sentence typically uses the verb be, and is followed by the past participle form of a main verb and the preposition by. The passive verb should follow the tense of the active verb. For example, if the active verb is in the simple present tense, the passive verb too is in the simple present tense.
- Active sentence: The snake has swallowed a rodent.
- Passive sentence: A rodent has been swallowed by the snake.
(Has been is a form of the verb be. Swallowed is the past participle of the verb swallow. The preposition by has to be used here; otherwise, no one knows what swallowed the rodent.)
- Active sentence: The mosquitoes are biting me tonight.
- Passive sentence: I am being bitten by mosquitoes tonight.
(Am being is a form of the verb be. Bitten is the past participle of bite.)
Passive sentences without by
The preposition by is not used when the person or subject performing an action is understood.
- Active: I left the groceries in the boot of my car.
- Passive: The groceries were left in the boot of my car.
(The car driver is certainly the person who left the groceries in the car)
- Active: They smuggle immigrants across the border.
- Passive: The immigrants were smuggled across the border.
(It is understood that the smuggling was done by smugglers, so the preposition by is not applicable here, unless the smuggling was carried out by a specific party that need to be named. )
Passive verb is transitive verb
Only verbs that take on an object (transitive verb) can be a passive verb. The following examples have sentences in the active voice. Converting them into passive sentences seems quite impossible to do as each of them has an intransitive verb that does not have an object.
The preposition by can be omitted and another preposition with can be used in its place to show that something is used to perform an action.
- Active: She cut the paper with a pair of scissors.
- Passive: The paper was cut (by her) with a pair of scissors.
- Active: He beat the prisoner with a metal bar.
- Passive: The prisoner was beaten with a metal bar.
Phrasal verb in the passive voice
Not all phrasal verbs can be used in passive sentences but many can. Two phrasal verbs are used here:
knock down and look down on.
- Active: They knocked down the front wall for some renovation work.
- Passive: The front wall was knocked down for some renovation work.
- Active: He feels his family looks down on him because he has little formal education.
- Passive: He feels he is being looked down on by his family because he has little forma education.