Construction of the passive
The passive is a grammar construction that uses the auxiliary to be and the past participle of a verb:
- My camera has been stolen.
- The Mona Lisa was painted in 1503.
- We are being followed.
- She was seriously injured in the car crash.
- You will be told when to come.
- The school was built just after the war.
- The ski race has been cancelled due to lack of snow.
It is common to omit the auxiliary (and relative pronoun) when the passive is in a relative clause. For example:
- She is a teacher liked by everyone (who is liked...).
- The cat injured in the crash has now recovered (that was injured...).
First common use of the passive
The passive has two common uses. Firstly, @ we use the passive when we are more interested in what happened than who did it.~ For example, in saying My camera has been stolen the speaker is conveying important information about his camera. The camera is the focus of interest, and so the speaker has made it the subject of the sentence. He does not know or care who took it.
Similarly, in the sentence The Mona Lisa was painted in 1503 the speaker wants to tells us when the painting was done. She is not interested in telling us who painted it, or maybe she expects us to already know that it was painted by Leonardo da Vinci.
Examples of the passive in all tenses
The passive can be used in all tenses. The following list has examples of the most common uses:
- The classrooms are cleaned every afternoon. (present simple)
- A new road is being built behind the school. (present continuous)
- The boy was seen spraying paint on the wall. (past simple)
- I was late because the road was being repaired. (past continuous)
- The car thief has been caught. (present perfect)
- The painting had been damaged during the war. (past perfect)
- You will be shown how to do it. (future)
- It must be done. (modal verb + simple infinitive)
- She likes to be praised when she does well. (infinitive with to )
- I hate being watched when I'm working. (gerund)
Note: In all the above sentences, it is not important to the speaker that s/he tells us who (e.g., who cleans the classrooms, who is building the road behind the school, who saw the boy spraying paint). Important is: what (or when, why, how).
Second common use of the passive
The second important reason why we use the passive is to follow the typical English sentence pattern of Given-New. This means putting given or old information at the beginning of the sentence (as the subject), and following it with new information (as the predicate). Example:
The second world war began in September 1939. It was caused by the invasion of Poland by German troops. At this time Poland was governed by the Polish Socialist Party.
Here is the alternative, putting the new information before the given or old, and using the active not passive voice:
The second world war began in September 1939. The invasion of Poland by German troops caused it. The Polish Socialist Party governed Poland at this time.
Most native speakers of English find this kind of text unusual and hard to read.
Style advice on using the passive
Note: You may read advice against using the passive. For example, Microsoft's grammar checker in Word alerts you to uses of the passive. From this you may get the false idea that the passive is bad and should be avoided at all costs. This is not true.
If you want to read more about the passive, and when and how to use it, this UNC Writing Center webpage is an excellent starting point.
Also highly recommended are the series of videos on the passive by Professor Pullum, co-author of the authoritative Cambridge Grammar of the English Language:
Interactive quizzes for learning the passive
There are several interactive quizzes on the passive in the Verb grammar: Miscellaneous drop-down menu on the Grammar index.