The ProWritingAid Team
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Published Jan 24, 2019


As a writer, nothing irritates me more than the frequency with which I encounter typographical errors, misspelled words, incorrect word usage, and grammatical mistakes.

It's understandable: there's no time for proofreading when you're in full creative flow. But once your story's done, take a step back.

Have you made any of these top-ten grammatical errors in your manuscript? No worries! Here's how to fix them.


  1. Error #1: Commas
  2. Error #2: Subject/Verb Agreement
  3. Error #3: Pronoun Usage
  4. Error #4: Apostrophe Usage
  5. Error #5: Colons and Semicolons
  6. Error #6: Your vs. You’re
  7. Error #7: Its vs. It’s
  8. Error #8: Their vs. There
  9. Error #9: Which vs. That
  10. Error #10: Who vs. Whom

Error #1: Commas

The most abused error is the incorrect use of commas. Commas are used (1) to separate words in a list; (2) to join compound sentences; and (3) after introductory phrases.

With compound sentences, each clause can stand on its own as a separate and complete sentence. In these cases, a comma must be used to divide the clauses.

You should also use a comma after introductory phrases, such as after, although, however, indeed, unless, before, but, and, yet, so, etc. Otherwise, the passage becomes a run-on sentence.

A good rule of thumb is: If you pause when you say the sentence, a comma goes where you paused.

Error #2: Subject/Verb Agreement

Simply, they must agree. It is incorrect to say: “The teacher are strict.” It should be, “The teacher is strict.”

Error #3: Pronoun Usage

This is when the pronoun does not agree in number with the noun to which it refers. For example, it is incorrect to say, “Each of us are getting good grades.” The correct sentence: “Each of us is getting good grades.”

Error #4: Apostrophe Usage

Apostrophes denote possession, but they are never used after a possessive pronoun, such as his, hers, their, theirs, yours or ours. Example: “Her store is across the street from his’ store” is incorrect. It should be, “Her store is across the street from his store.”

Error #5: Colons and Semicolons

Colons should be used to introduce lists, explanations, or sometimes quotations. Semicolons should be used to connect independent clauses. People tend to confuse their functions.

Error #6: Your vs. You’re

This is a common error. “Your” is a possessive pronoun, as in “your daughter” or “your cat.” “You’re” is a contraction that means “you are,” as in “you’re annoying me by misusing your when you mean you are.”

Error #7: Its vs. It’s

The same principle applies here, and the mistake is just as commonplace. Only use the apostrophe when you mean "it is."

Error #8: Their vs. There

“There” can either be an adverb, adjective, or pronoun depending on how it is used, and usually indicates place. “Their” is a plural possessive pronoun.

Error #9: Which vs. That

“Which” introduces non-restrictive clauses; i.e., an additional, but not necessarily essential or crucial, part of a sentence. The word “that” introduces restrictive clauses; i.e., the necessary parts of a sentence that cannot be removed. Confusing their usage is a common mistake made by experienced and novice writers.

Error #10: Who vs. Whom

Both of these words are pronouns, but “who” refers to the subject of a sentence, while “whom” refers to the object of a sentence. In English, subjects do the action, while objects receive the action. It is incorrect to say, “Who did you talk to?” Also incorrect is “Whom wrote that book?”

In conclusion, I admit that English is not an easy language to master. So, if this article has helped you in any way, here’s to your improvement. Happy writing!

(Guest post by ArtistRJ19)

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The ProWritingAid Team
ProWritingAid: A grammar guru, style editor, and writing mentor in one package.

The most successful people in the world have coaches. Whatever your level of writing, ProWritingAid will help you achieve new heights. Exceptional writing depends on much more than just correct grammar. You need an editing tool that also highlights style issues and compares your writing to the best writers in your genre. ProWritingAid helps you find the best way to express your ideas.

I totally agree with all of these. We need more awareness of how to use the English language

By writersneed2 on 02 October 2012, 10:39 AM

What's error number 5?

By deblubin on 05 October 2012, 09:42 AM

According to writing manuals for research papers and academic journal articles (which most college students learn), the final serial comma with three or more items is required (for example, APA, MLA, and the Chicago Manual of Style), but many journalists seem to ignore these formal writing requirements because they usually follow the AP Stylebook. I don't think we can fault writers for using the final serial comma or not using it in general writing (say, fiction or business writing) since this difference is so minor.

By vmiskell on 14 November 2012, 04:57 AM