Comparisons are a special case of parallelism. A number of comparison-specific constructions call for you to always express ideas in parallel form. These constructions include:
- Either X or Y…
- Neither X nor Y…
- Not only X but also Y…
X or Y can stand for as little as one word or as much as an entire clause, but in every case, the grammatical structures of X and Y must be identical. For example, this sentence violates the rule by mismatching verb forms:
This is a comparison governed by the structure Either X or Y, which requires parallelism between X (“drinking”) and Y (“to eat”). Both verbs must be in the same form; because they aren’t currently in the same form, one must be adjusted.
Both X and Y are now in the –ing form. While in many cases, you could use two infinitives – to drink and to eat – this particular context calls for two gerunds (verbs acting as nouns).
Here’s another example:
Neither an interest in history nor to be adept in a foreign language is going to help you learn to sing.
This sentence lists two talents one could possess in a neither/nor format. They are not, however, in the same form.
In this sentence, a noun is compared to a verb. Though it’s a different kind of mistake than the missing-information and verb-form errors we’ve looked at, it should be dealt with in the same way: by changing one of the forms to match the other.
Both X and Y are now in the same form: an interest and adeptness. These two nouns make the comparison balanced and grammatical.
Incorrect: Neither an interest in history nor to be adept in a foreign language is going to help you learn to sing.
Correct: Neither an interest in history nor adeptness in a foreign language is going to help you learn to sing.
When you see comparison structures like Either X or Y, Neither X nor Y, or Not only X but also Y, check to make sure that X and Y are parallel.
Match nouns with nouns, verbs with verbs, etc. Make sure that the basis of comparison is the same for X and Y.
Comparisons as Parallelism
Best viewed in landscape mode
3 questions with video explanations
100 seconds per question
Are you sure you want to refresh the question?
Choose the correct answer.
Press SELECT to start video.
Be sure to turn on your volume to hear the explanation.