Ten Common Grammatical Mistakes in Writing

Take time to correct these ten common grammatical mistakes in writing

Ten Common Grammatical Mistakes in WritingWhen I was at University, I quickly learned that grammar was often the difference between a marginal grade and getting a good grade.  Regardless of the content, if people find your article hard to read, then they won’t read it.

Do yourself a favor.  Take a little time to correct grammatical mistakes in writing.  Your readers will reward your effort.

Professional writers need to pay special attention to grammar.  Writers will be judged on their grammatical errors; however, good the quality of the story can be.

1. Subject-Verb agreement

The subject and verb of a sentence must be in agreement.  If the subject is singular, then the verb must also be singular.  If the subject is plural, then the verb must be plural.

An example is the use of the words ‘have’ and ‘has.’

A sentence that does not have a subject-verb agreement is:

‘An important part of my life have been the people who supported me.’

A sentence that has subject-verb agreement is:

‘An important part of my life has been the people who supported me.’

2. Sentence fragments

Sentence fragments are incomplete sentences.  Sentences should have one independent clause.  Fragments may lack a subject or a verb, or both verb and subject.

Example of a sentence fragment:

‘His mother was tired.  And he didn’t visit.’

In this example, the second sentence depends on the first sentence to make sense.  The second sentence lacks a subject.

Example of a correct sentence:

‘He did not visit his mother because she was tired.’

3. A Comma should be used after an introductory element

A comma gives the reader a chance to pause and help make the sentence make sense.

Example of a missing comma:

For the last time don’t forget to add the comma.’

Example of a correctly placed comma:

For the last time, don’t forget to add the comma.’

4.  Correct use of the Apostrophe in “It’s.”

It’s is an abbreviation for ‘It is.’  Without the apostrophe, it denotes possessive adjectives.

Example of incorrectly use of the apostrophe:

“Its nice weather today!”

Example of correct use of the apostrophe:

‘It’s nice weather today!’

5.  The proper use of a commas

Some examples of when to use a comma:

  • A comma separates two clauses in a sentence. A clause has both a subject, a verb, or a verb predicate.
  • The comma goes after the first clause.
  • Use a comma before any coordinating conjunction (and, or, but, etc.) that links two independent clauses.
  • Use a comma to offset appositives from the rest of the sentence.  Appositives give more information.  For example, “I was reading and saw an apostrophe, a type of punctuation, in a sentence.
  • Use a comma in a list of items

Example of a missing comma in a compound sentence:

“He studied very hard but he failed the exam.”

Example of a correctly placed comma in a compound sentence:

“He studied very hard, but he failed the exam.”

phrase comma



6. They’re vs. Their vs. There

They’re, there and their‘ can confuse writers.  It is confusing because they are ‘homophones’ which means they have the same sound but different meanings.  Even though they sound the same, they are not spelled the same.


Their – is the possessive case of the pronoun They.  An example is ‘They left their hats at home.’  Their is usually plural but can be singular with words such as someone.  An example is ‘Someone left their hat on the boat.’


There is an adverb such as ‘in or at that place.’  An example is, ‘She is there now


They’re – The words ‘They’ and ‘are’ joined together (contraction).  An example is ‘They’re at the train station.’

If you are ever confused about which to use

Remember that ‘Their’ contains heir; this indicates possession.

There – Take out the ‘T’ from there and you get here; these are words indicating a place.

They’re – has an apostrophe, which means that it is the product of two words.

7.  Your vs. You’re.

You’re with the apostrophe is an abbreviation of you are.  

An example is  ‘If you go outside, you’re likely to catch a cold.’

Your indicates possession.

An example is ‘Your raincoat is red.’

8. Whose vs. Who’s

Whose is the possessive form for the pronoun who. Who’s is two words joined together Who and is; this may seem simple, but people still have trouble because in English, the apostrophe followed by ‘s’ usually indicates the possessive form of a word.  For example, ‘The woman’s purse.’  However, this is not the case with who’s

When do you use ‘who’s’?

The first thing to figure out is if you need two words or one.  Substitute the words who’s with who is or who has.

For example, ‘who’s been sitting in my chair?’; this could be ‘who has been sitting in my chair?’.

When do you use ‘whose’?

The word is possessive and is often used as an adjective.  So in this case, use whose to clarify who owns something.

Whose can be used to describe a single person or several people.  Whose can also be used to describe inanimate objects such as ‘whose army?’.

Examples of sentences using whose

Whose house is this?

You and whose army?

The sparkle came from an emerald whose light shone brightly.

9. Who vs. Whom

“Who” is a subject pronoun.  We use “who” for the subject of a sentence.  “Whom” is an object pronoun.  We use “whom” for the object of a sentence.


“Who scribbled on the whiteboard?”.  The subject of the sentence is “Who”.

“The whiteboard was scribbled on by whom?”  The subject is the whiteboard.  The object is “whom.”

10. Where vs. Were vs. We’re vs. Wear

It is easy for English learners to mix up these words, they have similar pronunciation but different spelling and meaning.

Where means in or at what place?  

An easy way to remember where is to remember that it contains the word  ‘here’.  Where is the dog?

Were – is a second person past plural.  A good way to remember when to use ‘were‘ is that it is similar to ‘w are’,  Are is present tense, Were is past tense.  For example, “We were in the kitchen.” meaning “We used to be in the kitchen.”

We’re is a contraction of we are.  A good way to remember is the replace the apostrophe with the letter ‘a.’

Wear is to have on the body.  A good way to remember is that wear contains the word ear, a part of the body.

Click here to test your mastery of English Grammar


If you understand these ten common grammatical mistakes in writing, then you will have a higher chance of being a successful writer.  People are more likely to read content with correct grammar.  Remember to keep sentences short and to the point.

Summary of ten rules of grammar

  • Subject and Verb must be in agreement
  • Avoid Sentence fragments
  • A comma should be used after an introductory element
  • The correct use of the apostrophe in ‘it’s.’
  • The proper of a comma in a compound sentence
  • The correct use of ‘they’re,’ ‘their’ and ‘there.’
  • The correct use of ‘your’ and ‘you’re.’
  • The proper use of ‘whose’ and ‘who’s
  • Correctly using ‘who’ and ‘whom’ in a sentence

Recommended book for improving writing

On Writing Well should be on the bookshelf of any serious writer.  The advice is easy to understand and not academic.  Basic common sense is easily understood.

Every chapter contains information the aspiring writer needs to know.  He starts by making the most crucial point about wordiness, and each section covers a different aspect of writing.  The book is for anyone interested in writing, not just academics.  William’s book is a fun read; it is not a textbook.

Recommended books for learning and teaching grammar

Understanding and Using English Grammar by Betty Azar understandingEnglishGrammar
Grammarly. Correct your grammar as you type. Grammarly logo
English Grammar in Use by Raymond Murphy English Grammar in Use
The Blue book of Grammar and punctuation provides an easy to use guide with clear rules, real-world examples, and reproducible quizzes. thebluebookofgrammar

Aaron Skudder


  1. What a nice post you wrote! I really enjoyed reading it and I could not be silent about your post so I decided to leave my comment here and say Thank You! For sharing this quality post with others.
    Actually this is exactly the information that I was looking for information about the common grammatical mistakes and when I landed on your website and read this post, it answered all my questions in details.
    So I’m happy that you decided to write about this topic and share it with people. It’s very useful and can definitely be used as a great source for everyone who is interested in this topic.
    I will come back to your website again for sure and I’m looking forward to reading your new posts.)


  2. Well I must say that when I came across your post, I was not sure if I should read it. That is because I know that I have my own limitations for grammar. It is like a mental block from some good habits I never learned.

    Thank you for this informative post and I look forward to reading more of it when you expand it. In the meantime, I will bookmark it for future reference (and possible homework!).

    • Hi Irma
      Sorry for not responding earlier. I have new material that you may find useful. The posts are being updated regularly. Your feedback is appreciated.

  3. So many easy ways to get this one wrong, and even though I loved English as a subject, grammar was a common problem in my writing. Another easy mistake is you’re and your. Looking forward to seeing what other common mistakes make the list!

  4. Hi Aaron,
    just checking your site after you reviewed mine, man I wished I saw your’s first, great tool and insight on the English language, it seems very complicated but your examples are spot on,
    I have bookmarked your page for future reference and hope it expands volumes thanks T.C

    • Hi Tom
      Sorry for not responding earlier. How is your site? I am constantly updating the material on my site. There are many new posts on grammer and writing.

  5. Hi there, this is a great post. A lot of the issues you pointed out I’ve certainly noticed in my reading so this post would be a great resource. #5 explains why I see commas before the word “and”. I was taught that when you use the word “and” it doesn’t require a comma so I find I always notice it when I see it.

    • Thanks Tamika
      You do not always use a comma before ‘and’. Use a comma if you are listing more than two items.
      Thanks for your feedback. I am going to add more tips. Please keep checking for updates.
      Kind regards

  6. Hi, this is wonderful for people like me that sometimes have trouble with writing. I often wonder if I’m writing correctly but when I search online, the examples are often confusing. My biggest concern right now is when to use semicolons. Any tip would be much appreciated. Thanks again for the information!

    • Hi Sandy ness

      Thank you for your kind comment. People over-use colons. A colon can be used in conjunction before a comma-separated list. If you are not sure when to use a semi-colon, it is better to use a comma.

  7. Hello Aaron

    Thank you for the opportunity to visit your site. In my language I master grammar very well. Unlike others who disagree between the subject and the predicate for example. In English, it is much harder for me. Your post illuminated me. But I have a suggestion: to review point 5.
    This point is confusing to me. But obviously I understood the idea.
    All the best to you

  8. Great article, We all know how difficult grammar rules are, especially to beginners. It’s confusing because of the general rules and the exception to such rules. While there are tools like Grammarly and Pro Writing Aid that can help you correct your errors so that we can avoid common/grammar/mistakes in writing.

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