What
is passive voice?
In English, all
sentences are in either "active" or "passive" voice:
active: Werner Heisenberg formulated the uncertainty principle in 1927.
passive: The uncertainty principle was formulated by Werner Heisenberg in 1927.
In an active sentence,
the person or thing responsible for the action in the sentence comes first. In
a passive sentence, the person or thing acted on comes first, and the actor is
added at the end, introduced with the preposition "by." The passive
form of the verb is signaled by a form of "to be": in the sentence
above, "was formulated" is in passive voice while
"formulated" is in active.
In a passive sentence,
we often omit the actor completely:
The uncertainty
principle was formulated in 1927.
When
do I use passive voice?
In some sentences,
passive voice can be perfectly acceptable. You might use it in the following
cases:
1.
The actor is unknown:
The cave paintings of
Lascaux were made in the Upper Old Stone Age. [We don't know who made them.]
2.
The actor is
irrelevant:
An experimental solar
power plant will be built in the Australian desert. [We are not interested in
who is building it.]
3.
You want to be vague
about who is responsible:
Mistakes were made.
[Common in bureaucratic writing!]
4.
You are talking about
a general truth:
Rules are made to be
broken. [By whomever, whenever.]
5.
You want to emphasize
the person or thing acted on. For example, it may be your main topic:
Insulin was first discovered in 1921 by researchers at
the University of Toronto. It is still the only treatment available for
diabetes.
6.
You are writing in a
scientific genre that traditionally relies on passive voice. Passive voice is
often preferred in lab reports and scientific research papers, most notably in
the Materials and Methods section:
The sodium hydroxide
was dissolved in water. This solution was then titrated with hydrochloric acid.
In these sentences you
can count on your reader to know that you are the one who did the dissolving
and the titrating. The passive voice places the emphasis on your experiment
rather than on you.
Note: Over the past
several years, there has been a movement within many science disciplines away
from passive voice. Scientists often now prefer active voice in most parts of
their published reports, even occasionally using the subject "we" in
the Materials and Methods section. Check with your instructor or TA whether you
can use the first person "I" or "we" in your lab reports to
help avoid the passive.
When
should I avoid passive voice?
Passive sentences can
get you into trouble in academic writing because they can be vague about who is
responsible for the action:
Both Othello and Iago
desire Desdemona. She is courted. [Who courts Desdemona? Othello? Iago? Both of
them?]
Academic writing often
focuses on differences between the ideas of different researchers, or between
your own ideas and those of the researchers you are discussing. Too many
passive sentences can create confusion:
Research has been done to discredit this theory. [Who did the
research? You? Your professor? Another author?]
Some students use
passive sentences to hide holes in their research:
The telephone was invented in the nineteenth century. [I couldn't find out who invented the
telephone!]
Finally, passive
sentences often sound wordy and indirect. They can make the reader work
unnecessarily hard. And since they are usually longer than active sentences,
passive sentences take up precious room in your paper:
Since the car was
being driven by Michael at the time of the accident, the damages should be paid
for by him.
Weeding
out passive sentences
If you now use a lot
of passive sentences, you may not be able to catch all of the problematic cases
in your first draft. But you can still go back through your essay hunting
specifically for passive sentences. At first, you may want to ask for help from
a writing instructor. The grammar checker in your word processor can help spot
passive sentences, though grammar checkers should always be used with extreme
caution since they can easily mislead you. To spot passive sentences, look for
a form of the verb to be in your sentence, with the actor either missing or
introduced after the verb using the word "by":
Poland was invaded in 1939, thus initiating the Second
World War.
Genetic information is encoded by DNA.
The possibility of
cold fusion has been examined for many years.
Try turning each
passive sentence you find into an active one. Start your new sentence with the
actor. Sometimes you may find that need to do some extra research or thinking
to figure out who the actor should be! You will likely find that your new
sentence is stronger, shorter, and more precise:
Germany invaded Poland
in 1939, thus initiating the Second World War.
DNA encodes genetic
information.
Physicists have
examined the possibility of cold fusion for many years.
Sumber : http://www.writing.utoronto.ca/advice/style-and-editing/passive-voice
