Faulty parallelisms

Common student errors found with the parallel structure largely involve similar problems when their parallel elements (head words or phrases) belong to different types and/or parts of speech. In most cases, they can be easy to correct and explain.

This sentence actually contains two errors in two different parallel structures. The first structure do not like reading but *[to play] hinges on the fact that gerunds mostly have the function of abstract nouns, whereas infinitives have many adverbial characteristics. To correct this error, the infinitive to play needs to be turned into a gerund (playing) or the gerund reading into an infinitive to read to make it parallel to to play. The second error is somewhat more complex because it builds parallel construction between the two noun phrases play games and [...] other visual media. In this case, the structure would mean that young people play ... other visual media. However, visual media such as TV or the Internet cannot be played, but rather they are used. To correct this construction, the parallelism needs to be build on two verbs-play and use (or enjoy, rely on, depend on) instead of the noun phrases games and visual media.

Un-Parallel Nouns/Noun Phrases

*Pascal was a philosopher, law scholar, educator, scientist, and he studied mathematics.

In this sentence, the series of nouns is not parallel to the sentence he studied mathematics, which can simply be turned into another noun to match other elements: mathematician.

Unparallel Simple Sentences in a Compound Sentence

Other common types of errors entail partial parallelisms of two simple sentences. In the following example, the second construction exists the belief is a sentence without the subject that attempts to be parallel to the complete simple sentence this definition is obscure.

*For the public, this definition is obscure, and exists the belief that engineers are technical people who don't have much knowledge in anything.

Although the two simple sentences this definition is obscure and exists the belief... are intended to be parallel, they are not because the second sentence does not have a subject. Two corrections are possible: there exists [a] belief that or many believe that....

Un-Parallel Adjectives-Noun Noun Modifiers and Linking/be-verbs-Activity Verbs

Sentence (4) contains two different parallelism errors: Adjective noun modifiers do not form very good parallels to noun modifiers that are nouns. In addition, linking and be-verbs, which often involve predicative adjectives, do not get along with activity verbs (e.g., read, write, measure):

*In urban and high-expense settings, a proper treatment of wastewater is necessary and preserve a healthy environment.

The adjective urban is not parallel to the noun phrase high-expense, which can become highly expensive (or simply expensive). Similarly, the predicative adjective necessary does not match the verb preserve, nor does the first linking verb is (necessary) form a good parallel to the second activity verb preserve (a healthy environment). In this case, the second predicate phrase may need to be rewritten as in for the preservation of a healthy environment or to preserve a healthy environment without the conjunction and. In either variant, the meaning may be slightly different from that originally intended by the writer.

Un-Parallel Comparisons

One of the most confusing and difficult types of errors with the parallel structure entails faulty parallelism in complex comparisons in two conjoined sentences with omitted elements. The choice of
which elements to omit, which to retain, and which to replace can cause a variety of problems:

*The precipitation rates in Portland are lower than Seattle.

*The conventional treatment ofwastewater is more expensive than mechanical equipment.

*Math teaching in Japan is more intensive/thorough/better than the U.S.

In all these constructions, the necessary parallel (or replacement) elements have been omitted (i.e., the subject noun those/that + the preposition in or by means of; see the following complex prepositions):

The precipitation rates in Portland are lower than those in Seattle.

The conventional treatment ofwastewater is more expensive than that by means of mechanical equipment.

Math teaching in Japan is more intensive/thorough/better than that in the U.S.

Replacing the omitted elements can usually correct the errors. However, it is important to make students aware of the complex comparative parallel structures with than.