A quick refresher on the most common grammatical mistakes we all make
Every writer tries to write without making grammatical errors.
But readers are quick to notice grammar errors or spelling mistakes in any form of writing.
It doesn’t matter if you are writing a blog post, an article, a novel or even a social media post. You want to make sure people understand, appreciate and enjoy your work, so always double check.
Today, lots of people are taking up writing; either for pleasure or as a way to make an income. For new writers, it is essential to keep learning the writing craft.
But one of my pet peeves is having to read any text that is full of basic and very common mistakes. I get a lot of messages and emails from writers, and more than a few contain careless errors.
It doesn’t make a good impression on me when a writer fails to use standard capitalisation and punctuation.
However, sloppy writing and carelessness are not the same as trying hard to follow more complex grammar rules, but not quite getting them right all the time.
The best way to help you improve the quality of your writing is to use a premium grammar checker to help you. Grammarly is by far the most popular choice for experienced and new writers.
Another good option is ProWritinAid, which is becoming an attractive choice, particularly for authors.
However, an online checker will not find every error for you. You still have to make decisions about certain grammar points using your own judgement to make sure that you use a phrase or word correctly.
For writers who want to continue to improve, here are twenty common grammar mistakes that are easy to get wrong. We all make a few errors from time to time.
Luckily, they are all very simple to fix, if you know how.
1. Subject-verb agreement
The verb must agree with the subject of the sentence.
It is one of the most common grammatical errors. Especially when writing about teams, organisations, governments or companies. An error can also occur when plural subjects are separated.
Depending on the subject, even a good grammar check might get it wrong.
Barnes and Noble are one of the biggest bookstore chains in the United States. (Incorrect)
Barnes and Noble is one of the biggest bookstore chains in the United States. (Correct)
As you can see from the Grammarly Card above, the suggested correction is not accurate. You need to know the rule to make the right choice.
The Detroit Tigers are a Major League baseball team. (Incorrect)
The Detroit Tigers is a Major League baseball team. (Correct)
Waterstones are a British book retailer that operates 283 shops, mainly in the UK. (Incorrect)
Waterstones is a British book retailer that operates 283 shops, mainly in the UK. (Correct)
Jane Moore, Mike Smith as well as John Green is being promoted. (Incorrect)
Jane Moore, Mike Smith as well as John Green are being promoted. (Correct)
Note: In US English, collective nouns are always singular and not plural. However, in British English, the rule is not quite as rigid.
2. Tense agreement
Changing tense within a sentence is a common writing error. If a sentence starts in the present tense, it should not change to the past tense.
He starts the car and then accelerated away in a cloud of tyre smoke. (Incorrect)
He started the car and then accelerated away in a cloud of tyre smoke. (Correct)
Who said writing is easy? (Incorrect)
Who says writing is easy? (Correct) or Who said writing was easy? (Correct)
3. No comma after an introductory element
Words and phrases that come before the main clause in a sentence should be separated by a comma.
Just in case you are worried I’ll be home by twelve. (Incorrect)
Just in case you are worried, I’ll be home by twelve. (Correct)
Therefore I shall wait until I am called. (Incorrect)
Therefore, I shall wait until I am called. (Correct)
4. Split infinitives
Correct sentences should never separate the infinitive. What this means is that the “to” must stay directly connected to its verb.
I wanted to quickly dash off to the supermarket. (Incorrect)
I wanted to dash off quickly to the supermarket. (Correct)
Apologies in advance to Star Trek fans here.
To boldly go where no man has gone before. (Incorrect)
To go boldly where no man has gone before. (Correct)
5. Unclear pronoun reference
A pronoun refers to a specific noun in the previous sentence or clause. However, it is very easy to use an unclear pronoun, which can confuse a reader.
When Brad started arguing with Claude, he went red in the face. (Incorrect)
It is unclear who went red in the face. Brad or Claude?
When Brad started arguing with Claude, Brad went red in the face. (Correct)
Mary and Tom are going out again and thinking of getting married. This is why I am so upset. (Incorrect)
It is unclear what this refers to and why he or she is upset. Does it refer to going out or getting married, or to the fact that Mary is with Tom again?
Mary and Tom are going out again and thinking of getting married. I am so upset with Mary for even thinking about marrying Tom. (Correct)
6. Apostrophe use with it’s and its
It is one of the easiest mistakes to make in the English language. Not only that, it is sometimes difficult to notice the error when proofreading.
The word its is a possessive pronoun. Something must belong to it.
The word it’s is a contraction of it is.
The same error often occurs with your, and you’re, for the same reasons.
Its time we got moving. (Incorrect)
It’s time we got moving. (Correct) It is time we got moving.
It’s cover is made of beige leather. (Incorrect)
Its cover is made of beige leather. (Correct) The book cover is made of beige leather.
Your late for dinner again. (Incorrect)
You’re late for dinner again. (Correct)
You’re father will not be happy about this. (Incorrect)
Your father will not be happy about this. (Correct)
7. Parallel structure
Parallelism errors occur when parts of a sentence are comparable in meaning but not grammatically the same in form. It happens with joined constructions and things in a series.
I have been thinking about signing up to study phonetics, literary devices and an English teacher. (Incorrect)
I have been thinking about signing up to study phonetics, literary devices and English teaching. (Correct)
I really need to concentrate on grammar, spelling and my punctuating. (Incorrect) Mixing verbs and nouns.
I really need to concentrate on grammar, spelling and punctuation. (Correct) All nouns.
8. Dangling modifiers
Dangling or misplaced modifiers occur when poor adjective placement makes it unclear as to what noun it is describing.
I was on my way to work and noticed a cream woman’s handbag in the gutter. (Incorrect)
It is unclear if the handbag belongs to a cream woman or if the handbag is cream. The modifier needs to be moved next to the word it is modifying.
I was on my way to work and noticed a woman’s cream handbag in the gutter. (Correct)
My new girlfriend ordered an expensive plate of lobster at the restaurant last night. (Incorrect)
The plate was not expensive. It was the lobster.
My new girlfriend ordered a plate of expensive lobster at the restaurant last night. (Correct)
9. Sentence fragments
The common causes of this error are that the sentence or clause requires a subject-verb construction, or there is a separated prepositional phrase or dependent clause.
Looking forward to meeting you next Sunday. (Incorrect)
I’m looking forward to meeting you next Sunday. (Correct)
I found great a new position in tech. The remedy for all my financial problems. (Incorrect)
I found great a new position in tech, which will be the remedy for all my financial problems. (Correct)
10. A run-on sentence
A run on sentence is also called a fused sentence.
The mistake happens when two independent clauses, which are, in fact, complete sentences, are joined without being properly connected.
Using conjunctions such as and, but, for, nor, yet, or, because can usually fix the problem.
The next step will be tough, you should get ready as soon as you can. (Incorrect)
The next phase will be tough, so you should get ready as soon as you can. (Correct)
I can’t figure out how to set up this rice cooker, it came without an instruction manual. (Incorrect)
I can’t figure out how to set up this rice cooker because it came without an instruction manual. (Correct)
11. Unnecessary and redundant commas
Commas are not a punctuation mark you add just because it feels right, or where you think you should take a breath.
The most common mistake is to use them before conjunctions.
I rarely go to the city centre, because I hate the crowds. (Incorrect)
I rarely go to the city centre because I hate the crowds. Correct)
He says he wants to start a new course in writing, or literature. (Incorrect)
He says he wants to start a new course in writing or literature. (Correct)
12. The Oxford comma
The Oxford comma or serial comma is used to avoid confusion. It is generally used in lists to ensure that the last item is separated.
For dinner tonight, I will cook beef stew, new potatoes, green beans and ice cream. (Incorrect)
Without a comma, the green beans will be served with the ice cream.
For dinner tonight, I will cook beef stew, new potatoes, green beans, and ice cream. (Correct)
I was shocked to find myself alone with my teacher, a greenie and a vegetarian. (Incorrect)
There is only one person present in this sentence. My teacher, who is also a greenie and a vegetarian.
I was shocked to find myself alone with my teacher, a greenie, and a vegetarian. (Correct)
Now there are three people present. My teacher, a greenie, and a vegetarian.
13. Comma splice
A comma splice happens when two sentences are joined with a comma instead of a full stop (period) or semi colons.
Linking words, such as however, therefore, moreover, nevertheless, or furthermore are often a cause of the problem.
I wanted to go out for dinner before we went to the cinema, however I decided to go after instead. (Incorrect)
I wanted to go out for dinner before we went to the cinema. However, I decided to go after instead. (Correct)
My friends and I like to go skiing, we have so much fun together on the weekends in winter. (Incorrect)
My friends and I like to go skiing. We have so much fun together on the weekends in winter. (Correct)
14. Wrong word selection
Affect and effect and accept and except cause the most significant problems. Be careful with commonly confused words and make sure you use the right word in the context of your sentences.
John excepted with pleasure his generous offer to start in a new more senior position. (Incorrect)
John accepted with pleasure his generous offer to start in a new more senior position. (Correct)
The book effected me so deeply, I cried. (Incorrect)
The book affected me so deeply, I cried. (Correct)
15. Colon errors
The colon is placed after a whole sentence to add a word, phrase, clause, list, or a quotation. The colon says that what follows proves or explains the sentence before a colon.
Retired people move south for: warmer weather, the beaches, and cheaper retirement living. (Incorrect)
Retired people move south for three reasons: warmer weather, the beaches, and cheaper retirement living. (Correct)
In summer I like to eat: ice cream and lettuce. (Incorrect)
In summer I like to eat two things: ice cream and lettuce. (Correct)
16. Em dash instead of an en dash
An en dash is most often used to indicate the sense of “through to” in dates or number sequences. Note that there is no space on each side of the dash.
The festival will be held 17–20th July.
Please refer to pages 247–522 for more in-depth details.
The main use of the em dash is to highlight information, which would often be enclosed in commas, parentheses or following a semi colon.
Liver, kidney and trotters are foods I just can’t eat.
Liver, kidney and trotters—all foods I just can’t eat.
Mary, Chris and Mark attended the meeting with the boss.
The three of them—Mary, Chris and Mark—attended the meeting with the boss.
17. Incomplete comparisons
This error occurs when you make a comparison, but it is not clear to what you are comparing.
Generally, if you make a comparison without including the word than it is incomplete.
Montreal is much colder. (Incorrect)
Montreal is much colder than Toronto. (Correct)
My brother is a lot older. (Incorrect)
My brother is a lot older than me. (Correct)
18. Sentence sprawl
Sprawling sentences are usually caused by connecting too many clauses or phrases with comma separators. It is almost always best to divide long sprawling sentences into shorter and clearer sentences.
Mike had intended to go to his neighbour’s wedding on August 30, but at the last minute he discovered that he had been called up for jury duty, so he wouldn’t be able to attend the wedding, and he felt dreadful about not being able to go. (Incorrect)
Mike had intended to go to his neighbour’s wedding on August 30. However, at the last minute, he discovered that he had been called up for jury duty. He knew he wouldn’t be able to attend the wedding. He felt dreadful about not being able to go. (Correct)
19. Missing comma in a compound sentence
When you join two independent clauses together with coordinating conjunctions such as and, but, or, nor, for, so or yet, you need to add a comma before the coordinating conjunction.
I understand that you need to work late nights but you really should find some time to relax. (Incorrect)
I understand that you need to work late nights, but you really should find some time to relax. (Correct)
The bank robber quickly got into a black SUV and he sped away from the crime scene before anyone noticed. (Incorrect)
The bank robber quickly got into a black SUV, and he sped away from the crime scene before anyone noticed. (Correct)
20. Less vs fewer
This is one of the most common grammar mistakes. So common that it is made by mother tongue English speakers all the time.
Have you noticed that many supermarkets have an “8 items or less” checkout? It is grammatically incorrect. It should read, “8 items or fewer”.
Less is used when referring to uncountable nouns. Fewer is used for countable nouns.
I have less friends than my sister. (Incorrect)
I have fewer friends than my sister. (Correct)
You have less opportunities for promotion in a government job. (Incorrect)
You have fewer opportunities for promotion in a government job. (Correct)
Writing well is not easy. You need to pay attention to every word or phrase you write and check carefully for any grammatical errors. If you make basic grammar mistakes, you will fail to win new readers.
Sure, you can use premium grammar checkers such as Grammarly or ProWritingAid to catch 95% of your writing errors. They both offer you a lot of help in reducing your mistakes.
But you still need to know what is right and wrong to make good decisions. Nothing improves your writing faster than developing your grammar knowledge.
The twenty common mistakes listed in this article are a great start. But keep working on adding to your grammar knowledge and understanding to make you an even better writer.