English 104: College Composition

Sentences that aren't parallel sound funny, even if they look perfectly correct at first glance. Learn what makes a sentence parallel, how to revise a sentence to make it parallel, and how to write beautiful, balanced sentences of your own.

Parallel Sentences

Have you ever been on a flight when an attendant asked you to move your seat to help balance the aircraft? If the attendants didn't do this, the plane would probably still fly, but you'd be in for a rough flight.

A sentence without parallel structure is like an imbalanced aircraft; it'll get you from point A to point B, but no one's going to congratulate the pilot when it lands.

Coordinating Conjunctions

To spot potential parallelism pitfalls, first look for the coordinating conjunctions in a sentence - those arefor, and, nor, but, or, yet, and so - and then look to either side of the conjunction to see if it's parallel. So here's an example of a sentence without parallel structure:

Deep-fried Oreos are delicious but bad nutrition.

So we have 'delicious' on one side and 'nutrition' on the other of the coordinating conjunction, but the former is an adjective and the latter is a noun. Here's the same sentence with parallel structure:

Deep-fried oreos are delicious but not nutritious.

Now both of the descriptors are adjectives and the sentence is balanced.

Parallel structure is about style. It's about the way that a sentence feels and flows. Yes, it's part of grammar, but it's also part of what makes an essay or a sentence sound good to the reader's ear.

Let's look at another example.

Correlative Conjunctions

Sentences that contain correlative conjunctions must also be parallel. So a correlative conjunction can take the form of either...or, neither...nor, both ... and, and not only ... but also. These pairings highlight a connection, or correlation, between two elements. Here's an example of a sentence that uses correlative conjunctions but is not parallel:

We not only were lost but also broke.

Now the correlative conjunction here is not only ... but also, and if you stick the verb were in the middle of it, it breaks it up and makes it not parallel. So there are two different ways you can balance this sentence.

You could do we not only were lost, but also were broke. You have two verbs and those are on either side of the coordinating conjunction, which is but, or you could stick the verb before the correlative conjunction: we were not only lost, but also broke.

The structures directly following the conjunctions have to match and that's the important lesson about parallel structure.

Items In A Series

One of the most common parallel structure mistakes occurs when writers list items in a series. You're bounding over the hills and dales of a sentence when suddenly, just before you reach your destination, the car hits a ditch. Here's an example:

Sasquatch enjoys taking long walks in the forest, playing with small woodland creatures, and to devour wandering tourists.

Now, instead of all -ing words - called gerunds - in the series, the sentence hits a hitch at the infinitive to devour. Matching the verb-forms restores the balance, so it should be:

Sasquatch enjoys taking long walks in the forest, playing with small woodland creatures, and devouring wandering tourists.

Isn't that better?

Clauses

In general, if you begin with a clause (that's a group of related words that contains a subject and a verb), you need to stick with that clause for the duration of the sentence to keep it parallel. So try this:

On the last night of awesome ninja training, the Master told his students that they must be stealthy, that they must be cunning, and to be quick.

This sentence is unbalanced because the infinitive to be quick is not parallel with the clause that they must be. To fix this, replace to be quick with the same clause as the other clauses in the sentence:

On the last night of awesome ninja training, the Master told his students that they must be stealthy, that they must be cunning, and that they must be quick.

Or, to make it more graceful - but still parallel - in this instance, you can just list the final adjectives of the clause:

On the last night of awesome ninja training, the Master told his students that they must be stealthy, cunning, and quick. That's ninja-esque.

Comparison Sentences

Comparison sentences can also be parallel or not parallel. For instance:

I like to time travel more than flying.

The two comparison elements here (to time travel and flying) aren't in the same grammatical form. To time travel is in the infinitive form, while flying is a gerund. To make the sentence parallel, use the gerund in both cases (those are those -ing words we talked about before).

I like time traveling more than flying.

Or you can use the infinitive form in both cases:

I like to time travel more than I like to fly.

Either way, the sentence is now balanced.

Verb Tenses

When writing parallel sentences, you also want to make sure your verb tenses are the same. As before, remember to look on either side of the conjunction or connecting phrase to make sure the forms match.

So, Jonathan had grabbed the stake and drove it into the vampire's heart is not parallel because had grabbed on the one side of the conjunction (and) is in the past perfect form, while drove is simply in past tense. Balance the verb forms to make the sentence parallel. Can you see it?

You should choose either Jonathan had grabbed the stake and driven it into the vampire's heart, orJonathan grabbed the stake and drove it into the vampire's heart. Either one is correct.

Lesson Summary

The most important thing to remember about parallel structure is not to mix forms, tenses, or passive and active voices. If you have all gerunds, stick with them; if you have all infinitives, or all adverbs, stick with those.

That way, you get through this lesson writing clearly, intelligently, and efficiently (that's parallel) instead of clearly, intelligently, and with efficiency (not parallel).