a) We use the passive when the person who does the action (the agent) is unknown, unimportant, or obvious from the context.
- The school will be built soon. (the agent is obvious)
b) We use the passive when the action is more important than the person who does it (= agent).
- Someone has stolen our car. (Active)
- Our car has been stolen. (Passive) (It is not important who stole our car but the result. Do not overuse “by”; it is unnecessary to include it every time.)
c) We also use the passive voice in formal and impersonal statements, as well as scientific writing. We are more focused on events and processes than on the agent.
- The meeting is postponed until next Monday.
- The office is closed at the weekend.
d) We also use it to avoid taking responsibility for an action. We do not want to say who/what is doing something.
- A lot of mistakes have been made in this article.
→ The agent can usually be omitted if it is not important or essential to the meaning of the sentence.
→ The passive voice can change the emphasis of a sentence.
- My wife has written a novel. (The focus is on ‘my wife’)
- The novel has been written by my wife. (The focus is usually on ‘a novel’, but if the speaker emphasizes the word ‘my wife’, then the focus is on her regardless of the position in the sentence)
Note! By or with?
If we want to say who did the action, we use by. In the case of an object, we use with.
- The novel was written by my wife. (the person=the agent)
- He was hit with a stone. (an object=an instrument)
Note! Two objects
Active: They gave me a present.
Passive: I was given a present.
The present was given to me.
There are two objects:
me is an indirect object (usually appears first in an active sentence)
a present is a direct object
Normally, it is the indirect object which becomes the subject of the passive sentence and it is very often a person. However, we can also use the direct object as the subject. The direct object is usually a thing. When the direct object becomes first, we put to in front of the indirect object.