15 Common Grammar Mistakes

For many, writing is undoubtedly fun and exciting to do until they come across grammar. Indeed, many of us find it quite difficult to maintain perfect grammar even after years of studying English. Some thoughts may sound good in our minds. But when they are already written, our original ideas end up the other way around. We discover that we have made several grammar mistakes which should not be there in the first place.

Keeping perfect grammar is a tedious job, especially to some. It is not enough that we learn the rules, but it is more important to use them more often in writing so that you will be able to master these rules. In this article, we are going to discuss 15 grammar mistakes that you may be doing unknowingly. We will also explain how you are going to apply these rules by citing several examples.

1. Your vs. You’re

This is actually one of the most – if the not the – most common grammar mistakes people usually make. “Your” signifies something that belongs to you. “You’re,” on the other hand, is just the contracted form of, “you are.” Since this pair of pronouns is a set of homophones, many people may be able to interchange them. Hence, be mindful of their definitions. Check out these examples.

Wrong: Your absent yesterday.

Correct: You’re absent yesterday. (indicating that you were absent yesterday)

Wrong: I believe that this is you’re laptop.

Correct: I believe that this is your laptop. (indicating that this laptop is yours)


2. Its vs. It’s

This is another set of homophones which frequently confuses writers. “Its” signifies something that belongs to a neutral noun. “It’s,” on the other hand, refers to the contracted form of “it is.” One of the two is a possessive pronoun while the other is a contraction. Take a long at the examples below.

Wrong: Its hot inside the laboratory.
Correct: It’s hot inside the laboratory.

Wrong: Have you seen it’s decorations?
Correct: Have you seen its decorations?

Notice how the meaning of the sentences would change if the wrong word has been used.


3. There vs. They’re vs. Their

The there- they’re-their homophone group has also confused a lot of writers. “There” is used to refer to the direction that is not here. It is also used to state the presence of something. “They’re” is the contraction of the term, “they are.” Finally, “their” refers to possession, something that belongs to them.

Since they have different definitions, you should know how each of them is used in sentences. Let us take for instance these sentences.

Wrong: Their are a thousand goats over they’re backyard.
Correct: There a thousand goats over their backyard.

Wrong: They’re boat collapsed because there clumsy.
Correct: Their boat collapsed because they’re clumsy.


4. Affect vs. Effect

Many writers would also commit a mistake of interchanging these two words together since they look and sound alike. However, these words mean different. Affect is a verb which means to influence or have an impact on. On the other hand, effect is a noun which means the consequence of an action or a cause.

Wrong: There is a direct affect of the heat in the experiment.
Correct: There is a direct effect of the heat in the experiment.

Wrong: How did this experience effect your personality?
Correct: How did this experience affect your personality?


5. Who vs. Whom vs. Who’s vs. Whose

For these four words, it is better to break them into four separate sentences.

“Who” is used when asking for a human being. The answer is usually the subject of the sentence. For instance, we ask, “Who built this city through rock and roll?” The answer is definitely a person.

“Whom” is used to describe someone who will receive something. The answer is usually the object of the sentence. For example, we ask, “To whom are you paying your lunch?”

“Who’s” is a contraction of, “who is.” For example, we would say, “Who’s the tallest man on the planet.

“Whose,” on the other hand, is a possessive term used when asking the owner of something. For instance, we say, “Whose shirt was present there?”

6. Less vs. Fewer

The difference between these two words depends on whether the object being described can be counted or not. “Fewer” is used when the objects can be counted. “Less” is used for objects which are not quantifiable. Let us look at these sentences, for example.

Wrong: There are less roads which have not been renovated yet.
Correct: There are fewer roads which have not been renovated yet. (roads can be counted)

Wrong: There is fewer happiness left in this world.
Correct: There is less happiness left in this world. (happiness cannot be counted)

7. Amount vs. Number

These words are used in the same way as “fewer” and “less” since these would refer to quantifiable and non-quantifiable objects. “Amount” would refer to objects which cannot be counted. “Number” would refer to objects which can be counted.

Wrong: Please get a number of water from the basin.
Correct: Please get an amount of water from the basin. (water cannot be counted)

Wrong: An amount of birds are flocking the tree.
Correct: A number of birds are flocking the tree. (birds can be counted)

8. Compliment vs. Complement

A lot of people, even writers for that matter, would mix these things up since they do sound the same and they both look alike. However, they mean differently. “Complement” refers to something that completes another thing. Meanwhile, “compliment” refers to a polite expression of admiration. To make things clearer, take a look at the following examples.

Wrong: He gave her a positive complement for her dress.
Correct: He gave her a positive compliment for her dress.

Wrong: Her voice did compliment the tonality of the choir.
Correct: Her voice did complement the tonality of the choir.


9. Between vs. Among

The term “between” is used to describe two things that are separated while “among” refers to things that are not clearly separated from each other because each of the objects belongs to a part of a group.

Hence, you choose between a pencil and a pen, but you choose among all the writing materials. Furthermore, you could choose between a blouse or a plain t-shirt, but you choose among the dresses.


10. Use of Commas

Many people also commit mistakes in their use of commas. There are instances when a comma is placed in a sentence which does not require it. There are also some sentences which require a comma, but people tend to skip it. Let us take a look at some examples.

Wrong: Danica chose to stay inside the house, because she was afraid of ghosts.
Correct: Danica chose to stay inside the house because she was afraid of ghosts.

Wrong: People tend to leave out commas but there are instances when they really need it.
Correct: People tend to leave out commas, but there are instances when they really need it.

11. Parallel Structure

Parallelism in sentences happens when two or more similar parts of the sentence are parallel in terms of grammar. Weak parallelism occurs when this does not happen. It is often present in a series of items.

Wrong: His everyday routine includes going to the grocery, visiting the doctor, and lift weights.
Correct: His everyday routine includes, going to the grocery, visiting the doctor, and lifting weights.

Take note that the words used to denote action should all end in -ing to exhibit parallelism.

12. Split Infinitives

An infinitive refers to the combination of the word “to” plus the verb. The split infinitive separates the combination with another word, usually an adverb. While there are no strict rules which prohibit split infinitives, many writers do not recommend this. This is because the sentence may sound awkward.

Wrong: He decided to quickly dash to the seashore for the annual games.
Correct: He decided to dash to the seashore quickly for the annual games.

13. Subject-Verb Agreement

One of the most basic rules of grammar is to make your subject and verb agree with each other. If the subject of the sentence is singular, then the verb must also be singular. If the subject of the sentence is plural, then the verb must also follow suit.

Wrong: The cabinets is going to be repainted tomorrow.
Correct: The cabinets are going to be repainted tomorrow.

Wrong: The most important among all the sayings were to seize the day.
Correct: The most important among all the sayings is to seize the day.

14. Unclear Use of Pronouns

When you replace a noun with a pronoun, be sure that its reference is clear as day so as not to confuse your readers as to the pronoun reference. Let us take a look at the sentence for example.

Wrong: Dorothy told her mother that she will be buying her bag.
Correct: Dorothy told her mother, “I will buy your bag.”

In the first sentence, it is unclear who will buy the dress and to whom the dress will be given. The second sentence clears it out.

15. Punctuations in Quotation Marks

In sentences involving dialogs, you should always place your punctuation marks inside the quotation marks and not outside them. Placing them outside is grammatically incorrect.

Wrong: “Tell me the reason”, she thought aloud.
Correct: “Tell me the reason,” she thought aloud.

Wrong: “Have I done something wrong to offend you”? The minister asked.
Correct: “Have I done something wrong to offend you?” the minister asked.


Whether you are a language enthusiast or casual writer, you should strive to maintain high standards of grammar. We love using Grammarly to make sure we’re writing properly and you can read more about our love of Grammarly in our review.


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  1. Useful post about grammar mistakes, It’s best to learn from other’s mistakes than to feel the urge to commit one by oneself & then think of learning. I think we’ve all made some of these mistakes to some degree or another..


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