Subsection 7.2.3 Problems with Parallelism
Parallel sentence structure is a common pattern used to illustrate two or more ideas, items, or phrases that are equally emphasized in a sentence. It’s helpful to use parallel structure when you want to include a list of something or apply a series of words, phrases, or clauses to the same adjective or pronoun. This condenses the sentence, making it more efficient and less repetitive. For instance, say Polly likes to do three things. One way of listing those three things would be to write, “Polly likes to read books, likes to drink coffee, and likes to pet cats.” But that’s a pretty tedious sentence. Instead, you could use parallel structure to condense the sentence: “Polly likes to read books, drink coffee, and pet cats.” In this sentence, “likes to” applies equally to the infinitive phrases “read books,” “drink coffee,” and “pet cats.”
However, sometimes it’s easy to lose yourself while using parallel sentence structure by being inconsistent with your word, phrase, or clause forms. For instance, consider this common incorrect rewriting of the above sentence: “Polly likes to read books, drink coffee, and petting cats.” This is incorrect parallel sentence structure because the word forms are not the same; “likes to” applies to reading books and drinking coffee, but not to petting cats because the verb “petting” takes care of itself. The sentence indicates that Polly “likes to read books,” “likes to drink coffee,” and “likes to petting cats,” which has too many active verbs (“likes to” and “petting”). By replacing the infinitive form of “to pet” with the gerund form “petting,” the sentence now doesn’t make very much sense. Sometimes inconsistent forms can be tricky to identify, especially when you have a series of complex clauses or phrases. Below are some common examples of parallel structure errors to watch out for.
Subsubsection Mixing Word Forms
The above sentence is an example of mixing word forms (to read, to drink, and petting). If you have a verb that applies to two or more of the items in the series, it must apply to all items equally in order to preserve correct parallel structure. Take the following example of mixing word forms:
“Oppenheimer is a relaxing place to study; it is calm, quiet, and has lots of windows.”
In this sentence, the attributes “calm” and “quiet” equally share the verb “is”: Oppenheimer “is calm” and “is quiet.” However, the last attribute in the series (“has lots of windows”), departs from this structure by introducing another verb, “has,” to characterize the attribute “lots of windows,” throwing the series out of balance. If “is” is applied equally to each attribute, Oppenheimer “is calm,” “is quiet,” and “is has lots of windows.” To fix this mixed word form, you must do one of two things: 1) either break up the attributes into two different items using the conjunction “and” or 2) arrange the attributes so they share a single verb and adhere to the parallel structure.
Examples of these fixes are shown below:
- “Oppenheimer is a relaxing place to study; it is calm and quiet and has lots of windows.”
- “Oppenheimer is a relaxing place to study; it is calm, quiet, and airy.”
Subsubsection Mixing Clause Forms
The same rule may be applied to a series of complex clauses. If you have a verb that applies to two or more clauses in the series, it must apply equally to all clauses in order to maintain parallel structure. Take the following example of mixing clause forms:
“This year, Diversions has cut a lot of paper waste by offering mug discounts, free Cup Karma drinks, more “for-here” options, and by encouraging people to recycle their coffee cup lids and sleeves.”
In this sentence, Diversions has cut a lot of waste by doing two things: 1) offering mug discounts, free Cup Karma drinks, and more “for-here” options and 2) encouraging people to recycle. While the first three clauses in the series (discounts, drinks, and options) all share the verb “offering” equally, the fourth clause (recycling lids and sleeves) only uses the verb “encouraging.” To correct this sentence to preserve parallel structure, you have to insert the conjunction “and” between the second and third clauses to distinguish what Diversions is “offering” from what it is “encouraging.” Take the corrected revision:
“This year, Diversions has cut a lot of paper waste by offering mug discounts, free Cup Karma drinks, and more “for-here” options and by encouraging people to recycle their coffee cup lids and sleeves.”
Subsubsection Two Nouns Following One Adjective
When you have two or more nouns following an adjective, that adjective must apply to all nouns equally. This can be a tricky mistake to identify; when we read, we often only think to apply the adjective to the noun that immediately follows it in the sentence. However, it’s important to make sure that either all nouns share the same adjective equally or each noun has its own adjective in a series. Take the following example of an adjective that is incorrectly applied to both nouns:
“The Cellar’s rambunctious atmosphere and array of ice cream flavors make it a good place to go to unwind.”
This sentence indicates that the adjective “rambunctious” applies to both “atmosphere” and “array of ice cream flavors.” While the first association makes sense, it would be strange to describe an array of ice cream flavors as “rambunctious.” Instead, both nouns must either share an adjective that describes both of them or they must have their own adjectives.
To fix this sentence, you can do one of two things:
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add an adjective that applies to “array of ice cream flavors”“The Cellar’s rambunctious atmosphere and diverse array of ice cream flavors make it a good place to go to unwind.”
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repeat the pronoun before “array” to prevent the misconception that it is a “rambunctious array”“The Cellar’s rambunctious atmosphere and its array of ice cream flavors make it a good place to go to unwind.”
Subsubsection Lists After a Colon
When you have a list after a colon, the parallel structure rule should be equally applied to all items in that list. Take this example of a list that does not follow parallel structure:
“The sandwich station at the SUB has the following spread options: hummus, pesto, mayo, mustard, and it also has relish.”
This list breaks parallel structure with the last item, “it also has relish,” which adds both a subject (“it”) and verb (“has”) to the list item (“relish”). To make this sentence adhere to parallel structure, the list item must be in the same form as the other items in the list:
“The sandwich station at the SUB has the following spread options: hummus, pesto, mayo, mustard, and relish.”
To avoid these and other parallel structure errors, here are some things to keep in mind while writing and proofreading:
- While writing a list or series, make sure every item in the series is grammatically consistent (all -ing endings vs. infinitive, passive vs. active voice, etc.).
- If you have an adjective or pronoun to describe the first word of a series, apply that descriptor equally to every item in the series to make sure it makes sense.
- Read carefully through your paper, paying close attention to series connected by conjunctions (“and”/“or”) and checking either side of the sentence for correct parallel structure.
- If you have a list or series, isolate every item into its own sentence, identify descriptors you can attribute to every item, and then condense the sentence accordingly.
