You’ve written, edited and read your paper out loud. The content you’ve included in this first research paper is golden, and you’re so proud of your work.

But then you show it to your friend to read, and she graciously points out a couple of mistakes that make you hit your head with your palm.

We all make grammar mistakes. In pursuing an education, or doing any report, email, write-up, etc. at work, mistakes are bound to happen.

But working to grasp the guidelines of grammar offers many benefits in addition to earning a better grade on your paper. According to a report compiled by Brock Haussamen, professor of English at Raritan Valley Community College of New Jersey, in the National Council of Teachers of English,

Grammar is important because it is the language that makes it possible for us to talk about language….As human beings, we can put sentences together even as children—we can all do grammar. But to be able to talk about how sentences are built, about the types of words and word groups that make up sentences—that is knowing about grammar. And knowing about grammar offers a window into the human mind and into our amazingly complex mental capacity.

Grammar is worth the time and effort to get it right.

Here are five common mistakes to check before submitting your paper.


Each of the students have their assignment.

Each of the students has their assignment.

When you read it, both sentences could make sense. But which one is correct?

In maintaining subject-verb agreement in sentences, singular subjects take singular verbs; plural subjects take plural verbs. But it’s not always easy to distinguish between singular and plural subjects. There may be interjecting phrases. And what about coordinating conjunctions and collective nouns?

Here are some important tips to keep in mind:

  • The indefinite pronouns anyone, everyone, someone and no one take a singular verb.
  • An interjecting phrase in a sentence doesn’t affect the subject-verb agreement.
  • “Doesn’t” is used with singular subjects; “don’t” is used with plural subjects.
  • When two or more subjects are connected by the conjunctions “or” or “nor,” the verb remains singular.
  • Collective nouns that refer to more than one person but considered a singular subject maintain a singular verb form.

When it comes to subjects and verbs in your sentences, make sure they get along.


Pronouns and possessive pronouns are something you’re bound to use in your paper or report. These are commonly misused in written works and everyday communication. To avoid confusion like Abbott and Costello’s “Who’s on First“, note these important differences:

  • Who—living pronoun, “Who wrote that beautiful paper?”
  • Whom—living pronoun on the receiving end of something, “To whom did you give your paper?”
    A quick tip: In answering a question, if you can replace “he” or “she” with the pronoun, use “who.” If you can replace “him” or “her” with the pronoun, use “whom.”
  • Whose—demonstrates ownership to someone, possessive pronoun—”She doesn’t know whose paper that is.”
  • Who’s—identifies a living person, contraction of “who is”—”Do we know who’s going to be in class?”


  • It’s—a contraction of “it is”—”She said it’s cold outside.” Use if you can substitute “it is” in the sentence—”She said it is cold outside.”
  • Its—possessive pronoun, indicates ownership—”The school loves its students.”

Confusion can come when working with other possessives, as many nouns take on an apostrophe + “s” to show possession, like the school’s students.


The comma. Like the apostrophe, it’s a small part of a sentence, yet it has powerful implications.

Perhaps you’ve heard of the example of how commas save lives, like in comparing these two sentences:

  1. “Let’s eat, Grandma.”
  2. “Let’s eat Grandma.”

The first sentence is a call to grandma to join them for a meal. The second sentence is a more unsavory declaration.

Here are some frequent comma mistakes to watch out for:

  • Missing comma—like in the “let’s eat Grandma” example. In introductory clauses, provide clarification by adding a comma.
  • Comma splice—when a comma joins two independent clauses. Make it easier on the reader and rather than piling on the commas, separate the sentences with a period. Or, add a conjunction and comma between the two clauses.
    • Incorrect: He wrote about his dog, she wrote about her bike.
    • Correct: He wrote about his dog, and she wrote about her bike.
  • Unnecessary commas—adding more commas is not always better. Don’t use commas to separate an independent and dependent clause, compound subjects or around interrupters.


Which of the following sentences sounds more interesting to you?

  1. The car was driven at night.
  2. The girl drove the car.

The first sentence is in passive voice. The verb phrase “was driven” feels disconnected from the subject, as the subject receives the action. Compare that to the second sentence, which is in active voice. The subject performs the action. It’s easier to visualize for the reader.

Using passive voice rather than active voice makes what you’re communicating more effective. To keep your reader, instructor, boss, co-worker engaged in your work, choose active voice over passive.


Grammar is more than just guidelines your professors hope you follow. They’re more than preferences your boss has in following a report. Grammar makes communicating easy and efficient. It helps us communicate with our classmates, supervisors, co-workers, peers and friends. It ensures we understand each other and are saying what we want to say, how we want to say it.

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