Have you ever read a sentence that contains a list and mentally tripped over one of the items? Did you notice that something wasn’t quite right, but you couldn’t figure out what it was?

It may have been that the listed items weren’t parallel.

What?

Sentence parallelism means that you use the same forms for words and phrases; in other words, all nouns, verbs, clauses, and tenses should match. For example, if you have a list of verbs and one of them ends in -ing, then all of your verbs should end in -ing (or, you should change the -ing verb to match the others).


Example: “I like swimming, knitting, and to cast spells.”

What’s the problem here? “To cast” does not match “swimming” or “knitting.” The correct version is: “I like swimming, knitting, and casting spells.”

Lists of verbs or nouns are fairly easy to check and correct, but clauses can be a bit tougher.


Example: “Our professor told us to study and that we should work on our assignments every night.”

It sounds okay, doesn’t it? The problem, though, is that “to study” is the infinitive form of the verb, and it does not match the auxiliary form of “should work.” The correct version is: “Our professor told us that we must study and that we should work on our assignments every night.” “Must” and “should” are both auxiliary verbs, so they match.


Correlative conjunctions, like “either / or,” “neither / nor,” “not only / but also,” might be the most confusing. I’ve seen many writers stumble over these.

Example: “They watched not only Firefly, but they also watched Serenity.”

In this case, the second clause splits up “but also” with a pronoun and adds an unnecessary verb. Since “not only” is followed by a noun (“Firefly”) in the first clause, the second needs to do so as well. The correct version is: “They watched not only Firefly, but also Serenity.”


Remember: parallelism creates clarity, balance, and flow in a sentence. If you can display these three things in your writing and editing, you’ll not only sound like you know what you’re doing, but also impress readers.