The Writing Lab
explains
PARALLEL STRUCTURE
A good writer uses parallel structure; that is, he or she puts nouns, verbs, phrases, thoughts,
and so on into a similar form. This is done primarily for style: it makes the writing easier to
read and in turn, easier for the reader to understand. Often, sentences that seem to be correct
but just sound wrong have a lack of parallelism at the core of their problem.
Some examples of parallel and non-parallel structure:
Nonparallel Parallel
Students spend their time going to classes,
studying, working, and they wish they had
time for a social life.
Students spend their time going to classes,
studying, working, and wishing for a social
life.
By the end of the quarter they're exhausted,
irritable, and have learned a lot. By the end of the quarter they're exhausted,
irritable and smarter.
BCC students hope for early registration
dates, and close-in parking spaces are
important, too.
BCC students hope for early registration
dates and close-in parking spaces.
The examples on the left give the impression that the writer is undecided or timid, afraid to
choose one form of expression and stick with it. The examples on the right give the
impression that the writer is at least confident enough to make a choice and keep to it.
Parallelism requires that an article (a, an or the) or preposition applying to all members of a
series must either appear before the first item only or be repeated before each item.
Nonparallel Parallel
a mark, a yen, buck or pound a mark, a yen, a buck or a pound
on Monday, Wednesday or on Friday on Monday, Wednesday or Friday
(on Monday, on Wednesday or on Friday)
Some words require that certain prepositions precede them. When such words appear in
parallel structure, it is important to include all of the appropriate prepositions, since the first
one may not apply to the whole series of items.
Nonparallel Parallel
His speech was marked by disagreement
and scorn for his opponent's position. His speech was marked by disagreement
with and scorn for his opponent's position.
(over)
Sentences with correlative expressions (both/and; not/but; not only/but also; either/or; first, second,
third) should employ parallel structure as well. Simple rewriting can often remedy errors in
these types of sentences.
