Common Sentence Errors

Common Sentence Errors


A statistical study of student writing performed in 1988 by scholars Andrea Lunsford and Robert Connors demonstrated that virtually 100% student writing mistakes are limited to 20 formal errors. Eliminating these errors in your writing therefore offers the quickest path to error-free prose.

1. Missing comma after an introductory element

Introductory words or clauses are usually set off with a comma:

  • Similarly Freire argues that memorization is dehumanizing.

  • Similarly, Freire argues that memorization is dehumanizing.


  • If the team wants to win they will have to practice more.

  • If the team wants to win, they will have to practice more.


2. Wrong word

  • The workmen assembled at the cite.

  • The workmen assembled at the site.


  • I have a bad case of ammonia.

  • I have a bad case of pneumonia.


3. Incomplete or missing documentation

Missing documentation for a quotation, summary, or paraphrase of another text may result in plagiarism, a serious academic infraction:

  • The response to the threat of terrorism should not be a curtailing of freedoms.

  • The response to the threat of terrorism should not be a curtailing of freedoms (Vindman 29).


4. Vague pronoun reference

  • The teacher gave her notes to her.

  • The teacher gave her notes to Jane.


5. Spelling error

  • I definately will be there.

  • I definitely will be there.


6. Faulty Parallelism

Parallel structure involves using the same form of words or structural pattern when crafting a sentence. In the example above, the author uses gerunds for the first two verbs but then changes to the infinitive form for the last verb. Generally, parallel structure sounds much better to the ear than otherwise:

  • He was good at swearing, fighting, and liked to drink.

  • He was good at swearing, fighting, and drinking.


  • They were informed that they should not eat before swimming, that they should not eat sugar, and to do some exercises before bed.

  • They were informed that they should not eat before swimming, that they should not eat sugar, and that they should not skip exercise before bed.


7. Unnecessary comma

Only use a comma before a coordinating conjunction if you are connecting two independent clauses:

  • The legal language applies to carnivals, but not amusement parks.

  • The legal language applies to carnivals but not amusement parks.


The phrase “who held the American flag” is a restrictive element—a part of a sentence that is essential its meaning. This information identifies the particular man who waved from all the others on the bus. Restrictive elements are not set off with commas.

  • The man, who held the American flag, waved to us from the tour bus.

  • The man who held the American flag waved to us from the tour bus.

8. Missing comma with a nonrestrictive element

A nonrestrictive element is a part of a sentence that is not essential to its meaning. Commas are used to set off these nonessential portions of the sentence:

  • The Boston Red Sox, who are my favorite baseball team, are having a rough time with middle relievers.

9. Missing comma in compound sentence

A compound sentence contains two or more clauses that can stand alone as complete sentences (otherwise known as “independent clauses”). However, to connect them as a single sentence you must either use a semicolon or a comma and a coordinating conjunction: for, and, not, but, or, yet, so. (You can remember these with the acrostic F.A.N.B.O.Y.S.) Failing to punctuate the compound sentence properly results in a fused, or run-on, sentence:

  • I am building a bunker in my backyard but I am not fearful of a zombie outbreak.

  • I am building a bunker in my backyard, but I am not fearful of a zombie outbreak.

10. Faulty sentence structure

When a sentence begins with a certain structure, then abruptly shifts to a different one, it becomes disorderly and difficult to follow.

  • With so much going on in the world today is why it is so hard to keep up with everything.

  • With so much going on in the world, it can be hard to keep up.

11. Unnecessary shift in verb tense

  • She ran to the store and picks up some milk.

  • She ran to the store and picked up some milk.

12. Lack of agreement between pronoun and antecedent

Pronouns and their antecedents must always agree in number. There are three rules that govern the choice between singular or plural pronouns: 1) Sentences that begin with an indefinite pronoun (such as everyone and each) are always treated as singular. 2) If antecedents are joined by or or nor, the pronoun must agree with the closer antecedent. 3) Collective nouns can be either singular or plural depending on whether the people are seen as a single unit or a group of individuals:

  • Each of the prisoners found happiness in their work.

  • Each of the prisoners found happiness in his work.


  • Either Jeff or Robert will be required to give up their car.

  • Either Jeff or Robert will be required to give up his car.


  • The campaign constantly changed its positions in the weeks before the election.

  • The campaign constantly changed their positions in the weeks before the election.

13. Missing or misplaced possessive apostrophe

  • The Baker Hill farm stand is proud to offer it’s vegetables for sale now.

  • The Baker Hill farm stand is proud to offer its vegetables for sale now.


  • The Sonic’s best player is Ubaldo Jimenez.

  • The Sonics' best player is Ubaldo Jimenez.

14. It’s / Its error

It’s is a contraction and means “it is” or “it has.” Its is the possessive form of it:

  • Its unfair to make him pay for all the damages.

  • It’s unfair to make him pay for all the damages.

15. Fused (run-on) sentence

A fused sentence is also known as a “run-on” sentence. It occurs when two clauses that could stand alone as complete sentences are placed together without punctuation:

  • Jeff was Wisconsin’s greatest dog trainer he could make a canine do virtually anything.

  • Jeff was Wisconsin’s greatest dog trainer; he could make a canine do virtually anything.

16. Comma splice

  • Dinosaurs once ruled the valley, they are all gone now.

  • Dinosaurs once ruled the valley, but they are all gone now.

  • Dinosaurs once ruled the valley; they are all gone now.

A comma splice occurs when two independent clauses are joined by a comma. To revise, use a comma with a coordinating conjunction or a semicolon.

17. Capitalization error

18. Poorly integrated quotation

Integrating quotations is challenging for most students. It is often the cause of grammatical or syntactical errors. When you integrate borrowed material into your own writing, the “hybrid” sentence you create must satisfy grammar and avoid awkward or repetitive phrasing:

  • Scholar Rod Andrews argues “I argue that there can be no reasonable discussions of Shakespeare’s biography” (99).

  • Scholar Rod Andrews argues that “there can be no reasonable discussions of Shakespeare’s biography” (99).

19. Unnecessary or missing hyphen

  • He bought a nineteenth century painting.

  • He bought a nineteenth-century painting.


  • His high-school was one of the best in the state.

  • His high school was one of the best in the state.

20. Sentence fragment

A fragment is an incomplete thought. It is a dependent clause treated as an independent one.

  • This school offers many classes. Such as Accounting and English.

  • This school offers many classes, such as Accounting and English.