6. Uses of the Passive: Active or Passive

A. The choice between active and passive constructions often depends on what has already been said, or on what the listener already knows. We usually like to start sentences with what is already known, and to put ‘new’ information

later in the sentence.

Compare these examples:

Alexander Graham Bell Telephone

British inventor who went to live Apparatus with which people can

in Canada and then in the USA. talk to each other over long distances

Bell invented the telephone. The telephone was invented by Bell.

Now let’s compare these two sentences from the examples:

Bell invented the telephone. The telephone was invented by Bell.

The two sentences have the same meaning, but they are about different things. The subject of one sentence is Bell, and the subject of the other is the telephone. The subject is the starting-point of the sentence, the person or thing we are talking about. In both of these sentences the subject is old information, something already mentioned.

The new information comes at the end of the sentence. We say Bell invented the telephone because we are talking about Bell, and the new information is that he invented the telephone.

When the subject is the person or thing doing the action (the agent), then we use an active verb (invented). When the subject is not the agent, then the verb is passive (was invented).

Compare:

Active (about Bell): Passive (about the telephone)

Bell invented the telephone. The telephone was invented by Bell.

Subject & agent Subject Agent

The subject of the passive sentence is the same as the object of the active sentence (the telephone). It is not the agent. It is the thing that the action is directed at.

B. We often prefer to put longer and ‘heavier’ expressions at the end of a sentence, and this can be another reason for choosing a passive structure. Compare:

Mary’s bahaviour annoyed me.

(Or: I was annoyed by Mary’s behaviour.)

I was annoyed by Mary wanting to tell everybody else what to do.

The first sentence can easily be active or passive. But if the second sentence was active, the subject would be very long (Mary wanting to tell everybody else what to do annoyed me). In this case, a passive structure is more natural.

C. Passive structures are also used when we want to talk about an action, but we are not interested in saying who (or what) did it.

Those pyramids were built around A.D.400.

D. Passives are very common in scientific writing, and other kinds of expression where we are most interested in events and processes: in things that happen. We see it especially in textbooks and reports. We use it to describe activities in industries, science and technology, and also for official rules:

Bananas are exported to the USA. The liquid is heated to boiling point.

Payment can be made at any post office. These gates will be locked at 9.00 pm.

The passive is often used in news reports:

A number of political prisoners have been released.

Negotiations will be held in London next week.