The 5 Most Common Grammar Mistakes and How to Fix Them

Even the most skilled writers occasionally stumble over grammar rules. Whether you're writing an important email, preparing a report, or crafting content for a website, grammatical errors can undermine your credibility and distract from your message. This guide highlights the five most common grammar mistakes and provides clear explanations and strategies to help you avoid them.

1. Subject-Verb Agreement Errors

Subject-verb agreement errors occur when the subject and verb in a sentence don't match in number (singular or plural).

The Problem

When the subject and verb don't agree, sentences sound awkward and unprofessional:

❌ Incorrect: "The group of students were late to class."
✅ Correct: "The group of students was late to class."

In this example, "group" is the subject (singular), not "students," so it requires a singular verb.

Common Tricky Situations

Collective Nouns

Words like team, family, committee, and staff can be confusing because they represent groups but are grammatically singular in American English:

❌ Incorrect: "The team are playing well this season."
✅ Correct: "The team is playing well this season."

Sentences with "Or" or "Nor"

When subjects are joined by "or" or "nor," the verb agrees with the subject closest to it:

❌ Incorrect: "Neither the students nor the teacher were prepared."
✅ Correct: "Neither the students nor the teacher was prepared."

Indefinite Pronouns

Some indefinite pronouns (everyone, anybody, nobody, someone) are always singular:

❌ Incorrect: "Everyone in the rooms were asked to leave."
✅ Correct: "Everyone in the rooms was asked to leave."

How to Fix It

1. Identify the true subject of the sentence (ignoring modifying phrases)
2. Determine if the subject is singular or plural
3. Choose a verb form that matches the subject

2. Comma Splice Errors

A comma splice occurs when two independent clauses (complete sentences) are joined with only a comma.

The Problem

Comma splices create run-on sentences that can confuse readers:

❌ Incorrect: "It was raining heavily, we decided to cancel the picnic."
✅ Correct: "It was raining heavily, so we decided to cancel the picnic."

How to Fix Comma Splices

You have several options to correct comma splices:

1. Use a Period to Create Two Sentences

"It was raining heavily. We decided to cancel the picnic."

2. Use a Semicolon

"It was raining heavily; we decided to cancel the picnic."

3. Add a Coordinating Conjunction (FANBOYS)

"It was raining heavily, so we decided to cancel the picnic."

The FANBOYS coordinating conjunctions are: For, And, Nor, But, Or, Yet, So.

4. Add a Subordinating Conjunction

"Because it was raining heavily, we decided to cancel the picnic."

Common subordinating conjunctions include: because, since, although, while, when, if, though.

5. Restructure the Sentence

"The heavy rain caused us to cancel the picnic."

3. Apostrophe Misuse

Apostrophes cause confusion when used incorrectly for possessives, contractions, and plurals.

The Problem

Misused apostrophes can change meaning or create nonsensical constructions:

❌ Incorrect: "The company reviewed it's policies."
✅ Correct: "The company reviewed its policies."

Common Apostrophe Mistakes

Confusing Its and It's

• It's = contraction of "it is" or "it has"
• Its = possessive form of "it"

❌ Incorrect: "The dog wagged it's tail."
✅ Correct: "The dog wagged its tail."

Using Apostrophes for Plurals

❌ Incorrect: "We sold ten apple's."
✅ Correct: "We sold ten apples."

Possessive Forms of Names Ending in S

For singular nouns ending in s, style guides differ:

• "James's book" (Chicago Manual of Style)
• "James' book" (AP Style)

Both can be correct depending on which style guide you follow.

How to Fix Apostrophe Errors

1. For contractions, use apostrophes to indicate missing letters: don't, can't, won't
2. For possessives, add 's to singular nouns: the student's paper
3. For plural possessives, add an apostrophe after the s: the students' papers
4. For the possessive of it, use its (no apostrophe)
5. Never use apostrophes to form plurals (except in rare cases like "mind your p's and q's")

4. Dangling Modifiers

A dangling modifier occurs when a descriptive phrase doesn't clearly or logically connect to the subject it's supposed to modify.

The Problem

Dangling modifiers create illogical or sometimes humorous sentences:

❌ Incorrect: "Walking down the street, the trees were beautiful."
✅ Correct: "Walking down the street, I thought the trees were beautiful."

In the incorrect version, the trees appear to be walking down the street!

Common Examples

❌ Incorrect: "After finishing the assignment, the TV was turned on."
✅ Correct: "After finishing the assignment, she turned on the TV."

❌ Incorrect: "Having worked all day, the bed was a welcome sight."
✅ Correct: "Having worked all day, I found the bed a welcome sight."

How to Fix Dangling Modifiers

1. Identify who or what is performing the action in the modifying phrase
2. Make sure that subject appears immediately after the comma
3. If necessary, rewrite the sentence completely to clarify who is performing each action

5. Pronoun Reference and Agreement Errors

Pronoun errors occur when pronouns don't clearly match their antecedents (the nouns they replace) in number, person, or gender, or when the reference is ambiguous.

The Problem

Unclear pronoun references confuse readers about who or what is being discussed:

❌ Incorrect: "Maria told Susan that she should apply for the job." (Who should apply?)
✅ Correct: "Maria told Susan that Susan should apply for the job."

Common Pronoun Issues

Ambiguous References

❌ Incorrect: "The managers discussed the project schedule with the developers, and they were concerned about the timeline." (Who was concerned?)
✅ Correct: "The managers discussed the project schedule with the developers, and the managers were concerned about the timeline."

Agreement in Number

❌ Incorrect: "Each student must complete their assignment."
✅ Traditionally correct: "Each student must complete his or her assignment."
✅ Modern acceptable usage: "Each student must complete their assignment." (singular "they" is increasingly accepted)

Vague "This" and "That"

❌ Incorrect: "The company changed their policy on remote work and hired new managers. This caused employee dissatisfaction." (What caused dissatisfaction?)
✅ Correct: "The company changed their policy on remote work and hired new managers. This policy change caused employee dissatisfaction."

How to Fix Pronoun Problems

1. Ensure each pronoun clearly refers to a specific antecedent
2. Check that pronouns agree with their antecedents in number and gender
3. When a reference might be unclear, repeat the noun instead of using a pronoun
4. Be aware that usage standards for pronouns are evolving, especially regarding gender-neutral language

Practical Tips for Avoiding Grammar Mistakes

1. Read Your Writing Aloud

Many grammar errors become obvious when you hear them. Reading aloud forces you to slow down and consider each word and phrase.

2. Take a Break Before Proofreading

Fresh eyes catch more errors. Step away from your writing before reviewing it.

3. Use Grammar Checking Tools as a First Pass

Tools like Plagly's Grammar Checker can identify many common errors, but don't rely on them exclusively.

4. Learn From Your Mistakes

Keep a personal list of the grammar errors you frequently make and review it while editing.

5. Ask for Feedback

Having someone else review your writing can help identify issues you might miss.

6. Focus on One Rule at a Time

If you're working to improve your grammar, concentrate on mastering one rule before moving to the next.

When Grammar Rules Are Changing

Language evolves, and some traditional grammar rules are becoming more flexible:

• Singular "they" is increasingly accepted for gender-neutral reference
• Split infinitives (like "to boldly go") are now generally acceptable
• Ending sentences with prepositions is often fine in modern writing
• Starting sentences with conjunctions (And, But, Or) is common in contemporary writing

While being aware of changing standards, consider your audience and context. Academic and formal business writing typically adheres to more traditional rules, while marketing copy and casual communication allow more flexibility.

Conclusion

Improving your grammar doesn't happen overnight, but awareness of these common pitfalls is the first step toward clearer, more effective writing. By addressing these five frequent grammar mistakes, you'll significantly enhance the quality and professionalism of your written communication.

Remember that good grammar isn't about rigid rule-following—it's about clear communication. When your writing is grammatically sound, your ideas take center stage, and you build credibility with your readers.

Consider using tools like Plagly's Grammar Checker to help identify these common errors in your writing. With practice and attention, you'll find yourself making fewer mistakes and writing with greater confidence.