Page 69 - Advanced English Grammar in Use

U s i n g p a s s i v e s

The choice between an active and passive sentence allows us to present the same information in
two different orders. Compare:
active • The storm damaged the roof. passive • The roof was damaged by the storm.
This sentence is about the storm, and This sentence is about the roof, and says what
says what it did. [The storm is the happened to it. (The 'agent' goes in a
'agent'.) prepositional phrase with by after the verb.)

D Here are some situations where we typically choose a passive rather than an active.
• When the agent is not known, is 'people in general', is unimportant, or is obvious, we prefer
passives. In an active sentence we need to include the agent as subject; using a passive allows us
to omit the agent by leaving out the prepositional phrase with by:
О • My office was broken into when I was on holiday, (unknown agent)
• • An order form can be found on page 2. (agent = people in general)
• These boxes should be handled with care, (unimportant agent)
• She is being treated in hospital, (obvious agent; presumably 'doctors')

• In factual writing, particularly in describing procedures or processes, we often wish to omit the
agent, and use passives:
• Nuclear waste will still be radioactive even after 20,000 years, so it must be disposed of
very carefully. It can be stored as a liquid in stainless-steel containers which are encased in
concrete. The most dangerous nuclear waste can be turned into glass. It is planned to store
this glass in deep underground mines.
• In spoken English we often use a subject such as people, somebody, they, we, or you even when
we do not know who the agent is. In formal English, particularly writing, we often prefer to
use a passive. Compare:
• They're installing the new computer system next month.
• The new computer system is being installed next month, (more formal)
Notice also that some verbs have corresponding nouns. These nouns can be used as the subject
of passive sentences, with a new passive verb introduced:
• The installation of the new computer system will be completed by next month.
• In English we usually prefer to put old information at the beginning of a sentence (or clause)
and new information at the end. Choosing the passive often allows us to do this. Compare
these two texts and notice where the old information (in italics) and new information (in bold)
is placed in the second sentence of each. The second text uses a passive:
• The three machines tested for the report contained different types of safety valve. The Boron
Group in Germany manufactured the machines.
• The three machines tested for the report contained different types of safety valve. The
machines were manufactured by the Boron Group in Germany.
• It is often more natural to put agents (subjects) which consist of long expressions at the end of
a sentence. Using the passive allows us to do this. So, for example:
• I was surprised by Don's decision to give up his job and move to Sydney.
is more natural than 'Don's decision to give up his job and move to Sydney surprised me.'

Forming passive sentences: Passive verb forms =