Parallel Structures

One of the most common writing errors made by non-native users of English is making sentences that are not parallel. We often mention items in a series, and it is important that the items in the series agree grammatically. Consider this sentence:

My mother is kind, generous and polite.

In this example, the items in the series are all the same type of word (kind, generous and polite are all adjectives), so we can say the sentence is ‘parallel’. A non-parallel structure is when one element in a series is not the same as the rest. While non-parallel sentences are not always grammatically incorrect, parallel sentences show a greater ability to write well.

Examples:

Example 1: My dog Fido is small, cute and quickly.

This sentence is not parallel because quickly is an adverb, while small and cute are adjectives. The correct sentence is: 

My dog Fido is small, cute and quick. (adjective, adjective and adjective).

Example 2: John was promoted because he worked diligently, quick and accurately.

The sentence is not parallel because diligently and accurately are adverbs, whereas quick is an adjective. The correct sentence is:

John was promoted because he worked diligently, quickly and accurately.

Example 3: Dave received an award for his dedication, talent and he worked hard.

The sentence is not parallel because he worked hard breaks the pattern of dedication and talent, which are nouns. The correct sentence is:

Dave received an award for his dedication, talent and hard work.