Past participles are used along with the modal verb be to form passive constructions, that is, constructions which describe what happens or happened to someone or something.
- He was hit by a falling rock.
- This letter was written by someone with a very good knowledge of English.
- I have been asked to speak to you about your complaint.
- The key was lost somewhere round about here.
In grammar, passive constructions are normally contrasted with active constructions.
Active and Passive
When the subject of a verb performs the action described by the verb, then the verb is said to be in the active voice.
- Simon saw you.
- I wrote the letter.
- My sister’s little boy broke my favourite vase.
- Pat has chosen the music for the concert.
- J К Rowling wrote the Harry Potter books.
- The squirrels have eaten my crocuses.
- Professor Dobson gave the main speech at the conference.
- Her enthusiasm has really encouraged me.
A verb in the active voice may have an object:
- Sue and Jane sang a beautiful French folksong.
- James was reading a book.
Equally, there may be no object:
- Sue and Jane sang beautifully.
- James was reading.
When the subject of a verb is the person or thing that undergoes or experiences the action described by the verb, or is the person or thing to whom or to which the action is done, then the verb is in the passive voice.
- You were seen by Simon.
- The letter was written by me.
- My favourite vase was broken by my sister’s little boy.
- The music for the concert was chosen by Pat.
- The Harry Potter books were written by J К Rowling.
- My crocuses were eaten by the squirrels.
- The main speech at the conference was given by Professor Dobson.
- I was really encouraged by her enthusiasm.
A passive verb is formed with the auxiliary verb be and the past participle of a lexical verb:
- They planted the tree in the garden. — The tree was planted in the garden.
- A fox killed my chickens. — My chickens were killed by a fox.
- Rangers beat Celtic 6-0. — Celtic were beaten by Rangers 6-0.
- A dog bit her. — She was bitten by a dog.
If there is another auxiliary verb in the verb phrase, it always precedes the passive auxiliary be:
- My chickens have been killed by a fox.
- She has been bitten by a dog.
- This job must be completed by the end of next week.
- I’m sorry, it Just can’t be done by then.
- The coat must have been left in the restaurant.
If there is an adverb in the sentence, it will often stand between the auxiliary verb be and the past participle:
- I was greatly encouraged by her enthusiasm.
- It is often said that Chinese is difficult to learn.
The verb and particle of a phrasal verb stand together in a passive construction, even if they are separated in the corresponding active construction:
- The police are looking into the fraud. — The fraud is being looked into by the police.
- The team’s recent successes have made up for their poor performance earlier in the season. — The team’s poor performance earlier in the season has been made up for by their recent successes.
- The robbers beat him up badly — He was badly beaten up by the robbers.
- The scandal brought the government down. — The government was brought down by the scandal.
Subjects and Objects with Active and Passive Verbs
The object of a verb in the active voice becomes the subject of a corresponding verb in the passive voice.
- The wind blew down my apple tree. — My apple tree was blown down by the wind.
- Her friends met her at the airport. — She was met at the airport by her friends.
The subject of a verb in the active voice becomes the complement of the preposition by in the passive voice.
- The wind blew down my apple tree. — My apple tree was blown down by the wind.
- Her friends met her at the airport. — She was met at the airport by her friends.
If a sentence with an active verb has both a direct object and an indirect object, it may be the indirect object that becomes the subject of the corresponding passive verb.
- Her grandmother taught her [indirect object] French [direct object]. — She was taught French by her grandmother.
- My mother gave me a camera. — I was given a camera by my mother.
- His parents promised him a new bike. — He was promised a new bike by his parents.
Otherwise in passive sentences, the indirect object is replaced by a phrase beginning with the preposition to:
- John was given a medal. — A medal was given to John. It was given to him by the Queen.
The noun or pronoun following the preposition by Is known as the agent. The agent denotes the person or thing that performs the action of the verb:
- John was killed by his brother [agent].
- John was killed by a falling rock.
- The picture was painted by me.
- The picture was badly damaged by the fire.
The by-phrase describing the agent should not be confused with a phrase beginning with with which describes what is used to carry out the action of the verb:
- John was killed with a hammer.
- The picture had been slashed with a knife.
The noun following the preposition with is known as the instrument.