3.2 Common Sentence Errors

Mistakes make a negative impression on a reader (and on a grade). The most common sentence errors are subject-verb agreement, modifier problems, and lack of parallel structure. By understanding parts of speech and sentence structure, these errors can be avoided.

Subject-Verb Agreement

“Subject-verb agreement” means the subject of a sentence and the verb of a sentence must agree with each other in number. For example:

Singular: The cat jumps over the fence.
Plural: The cats jump over the fence.

Errors in subject-verb agreement are common, especially when the subject of the sentence is separated from the verb by lots of other words. However, if we isolate the prepositional phrases (remember: subjects and verbs never appear in prepositional phrases), then it’s easier to see if the subject and verb agree.

The students with the best grades in the school wins the academic awards.
The puppy under the table is my favorite.

“students” and “wins” do not agree, but “puppy” and “is” do agree.

Modifiers

A modifier is a word, phrase, or clause that clarifies or describes another word, phrase, or clause. Adjectives and adverbs are modifiers. Phrases and clauses can also work as modifiers.

Two common modifier errors are misplaced modifiers and dangling modifiers. When these errors occur, readers become confused trying to figure out what the writer means.

A misplaced modifier is too far from the word or words it modifies.

Misplaced modifiers make a sentence awkward and sometimes unintentionally funny. For example:

She wore a bicycle helmet on her head that was too large.

This seems to say her head was too large. The modifying phrase “that was too large” should be closer to the word “helmet.” The modifier is misplaced.

Corrected: She wore a bicycle helmet that was too large on her head.

Here is another example:

The patient was referred to a physician with stomach pains. (Does the doctor have stomach pains? The modifier “with stomach pains” is too far from the word “patient.”)

Corrected: The patient with stomach pains was referred to a physician.

Another modifier problem is what is called a “dangling modifier.”

A dangling modifier describes something that isn’t in the sentence.

When there is nothing for the modifier to modify, it is said to “dangle.” For example:

Riding in the sports car, the world whizzed by rapidly. (Who is noticing the world whizzing by? There is something missing. The modifier “riding in the sports car” is dangling.)

Corrected: When Farzad was riding in the sports car, the world whizzed by rapidly.

Parallel Structure

When something is parallel to something else, they are similar in form. For example, two parallel lines look like this:

Parallelism in writing is when a similar structure is used in related words, phrases or clauses.

For example, these three phrases have parallel structure:

in the pool, in the forest, in the book

They feel balanced. Also, they are easy to read and remember.

Now look at these word groups:

in the pool, forests are green, book shelf

They are different from each other in structure. Notice how jagged it feels to read them, and they are more difficult to remember.

Parallel structure creates rhythm and balance within a sentence. An unbalanced sentence sounds awkward. Read the following sentences aloud:

Kelly had to iron, do the washing, and shopping before her parents arrived.

Driving a car requires coordination, patience, and to have good eyesight.

Swimming in the ocean is much tougher than a pool.

All of these sentences contain faulty parallelism. They are clunky and confusing. In the first example, three different verb forms are used (“had to iron,” “do the washing,” “shopping”). In the second example, the writer begins with nouns (“coordination,” “patience”), but ends with a phrase (“to have good eyesight”).  In the third sentence, the writer is comparing an action (“swimming”) with a thing (“a pool”).

Here are the same sentences with correct parallelism:

Kelly had to do the ironing, washing, and shopping before her parents arrived. (The verbs have the same structure.)

Driving a car requires coordination, patience, and good eyesight. (The three qualities are all written as nouns.)

Swimming in the ocean is much tougher than swimming in a pool. (One action is being compared with another action.)

When sentences use parallel structure, they sound more pleasing. Repetition of the pattern also minimizes the work a reader has to do to understand the sentence.