Common Grammar Mistakes in English Writing

Good grammar is one of the most essential parts of effective English writing. However, even advanced learners and native speakers make mistakes from time to time. Understanding the most common grammar mistakes — and how to fix them — can help you write more clearly and professionally. In this guide, we’ll explore the most frequent grammar errors in English writing, with examples and easy-to-follow corrections.

1. Subject-Verb Agreement Errors

This is one of the most common grammar mistakes. The verb must agree with the subject in number (singular or plural).

Wrong:
The list of items are on the desk.
Correct:
The list of items is on the desk.

Why it happens:
Writers often get confused by words that come between the subject and the verb. In this example, “of items” is a phrase between the subject (“list”) and the verb.

Tip:
Always identify the true subject of the sentence before choosing your verb.

2. Misusing Tenses

Many learners mix past, present, and future tenses within the same paragraph or sentence.

Wrong:
I was studying English for three years and am moving to Canada last month.
Correct:
I was studying English for three years and moved to Canada last month.

Tip:
Be consistent. If you start describing a past event, keep your verbs in the past tense unless you are referring to something still true now.

3. Wrong Use of Articles (“a,” “an,” “the”)

Articles cause trouble for many non-native speakers because not every language uses them the same way.

Wrong:
I bought the new phone yesterday. (if you mean any new phone)
Correct:
I bought a new phone yesterday.

Wrong:
She is a best student in the class.
Correct:
She is the best student in the class.

Tip:

Use “a” or “an” for non-specific nouns.
Use “the” when the noun is specific or known to both writer and reader.

4. Confusing “There,” “Their,” and “They’re”

These three words sound the same but have different meanings and spellings.

There = a place or position
→ The book is over there.
Their = belongs to them
→ It’s their decision.
They’re = contraction of “they are”
→ They’re learning English online.

Tip:
Say the sentence out loud. If “they are” fits, use they’re.

5. Confusing “Your” and “You’re”

Another classic mistake that appears even in professional writing.

Wrong:
Your welcome to join the meeting.
Correct:
You’re welcome to join the meeting.

Tip:
If you can replace the word with “you are,” use you’re.

6. Overusing or Misplacing Commas

Commas help organize your sentences, but too many can make them confusing.

Wrong:
After dinner, we watched, a movie, and ate, dessert.
Correct:
After dinner, we watched a movie and ate dessert.

Tip:
Use commas:

After introductory phrases (e.g., “After dinner,”)
Between items in a list
Before conjunctions (like “and,” “but,” “or”) joining two independent clauses

Avoid placing commas where they interrupt the natural flow of the sentence.

7. Sentence Fragments

A sentence fragment is an incomplete sentence that lacks a subject or verb.

Wrong:
Because I was tired.
Correct:
Because I was tired, I went to bed early.

Tip:
A complete sentence needs both a subject and a predicate (a verb and the rest of the clause).

8. Run-On Sentences

Run-on sentences join multiple ideas without proper punctuation or conjunctions.

Wrong:
I went to the store I bought milk.
Correct:
I went to the store, and I bought milk.

Tip:
Connect ideas correctly using a period, semicolon, or a conjunction (like “and,” “but,” “so”).

9. Misusing Prepositions

Prepositions are small but tricky words. Using the wrong one changes the meaning.

Wrong:
She’s good in English.
Correct:
She’s good at English.

Wrong:
I’m waiting on the bus.
Correct:
I’m waiting for the bus.

Tip:
Memorize common expressions (“interested in,” “afraid of,” “rely on”) because prepositions often depend on fixed usage, not logic.

10. Incorrect Word Forms

Sometimes the wrong form of a word is used — for example, using an adjective instead of an adverb.

Wrong:
She sings beautiful.
Correct:
She sings beautifully.

Tip:

Use -ly for adverbs that describe verbs.
Use adjectives for nouns.

11. Double Negatives

Using two negatives in one sentence makes it confusing or grammatically incorrect.

Wrong:
I don’t need no help.
Correct:
I don’t need any help.

Tip:
In English, two negatives make a positive. Avoid using more than one negative word in a sentence unless it’s intentional (for style).

12. Confusing Countable and Uncountable Nouns

Wrong:
There are many informations about the topic.
Correct:
There is much information about the topic.

Tip:
Uncountable nouns (like “advice,” “news,” “equipment,” “information”) don’t take plural forms or use “many.”

13. Dangling Modifiers

A dangling modifier happens when a descriptive phrase doesn’t clearly refer to the right noun.

Wrong:
Driving to work, the rain started pouring.
Correct:
While I was driving to work, the rain started pouring.

Tip:
Make sure the modifying phrase refers directly to the subject of the sentence.

14. Incorrect Comparatives and Superlatives

Wrong:
This is more better than that.
Correct:
This is better than that.

Wrong:
He is the most fastest runner.
Correct:
He is the fastest runner.

Tip:
Never use “more” or “most” with words already ending in “-er” or “-est.”

15. Confusing “Its” and “It’s”

Wrong:
The cat lost it’s tail.
Correct:
The cat lost its tail.

Tip:

It’s = “it is” or “it has.”
Its = possessive form (belongs to “it”).

16. Using “Me” Instead of “I” (or Vice Versa)

Wrong:
Me and my friend went to class.
Correct:
My friend and I went to class.

Wrong:
She gave the gift to John and I.
Correct:
She gave the gift to John and me.

Tip:
Remove the other noun and test the sentence: “Me went to class” (wrong), “I went to class” (right).

17. Overusing Passive Voice

Passive voice isn’t wrong, but too much of it makes writing unclear or impersonal.

Example (Passive):
The project was completed by the team.
Example (Active):
The team completed the project.

Tip:
Use active voice when possible to make writing more direct and engaging.

18. Using “Less” Instead of “Fewer”

Wrong:
There are less students today.
Correct:
There are fewer students today.

Tip:

Use fewer with countable nouns (students, cars, books).
Use less with uncountable nouns (water, time, money).

19. Apostrophe Confusion in Plurals

Wrong:
Banana’s for sale.
Correct:
Bananas for sale.

Tip:
Apostrophes show possession or contractions, not plurals.
Example: “John’s car” (possession), “don’t” (contraction).

20. Overuse of “That”

Writers often add “that” unnecessarily.

Wrong:
I think that you should try harder.
Correct:
I think you should try harder.

Tip:
If removing “that” doesn’t change the meaning, it’s safe to leave it out.

Final Thoughts

Grammar mistakes happen to everyone, but being aware of them helps you catch and correct them. When writing in English:

Read your sentences out loud.
Use grammar check tools, but don’t rely on them completely.
Review common patterns where you often make mistakes.

Improving grammar is a gradual process, but each correction strengthens your confidence and clarity as a writer. With consistent practice and careful attention, your English writing will become both accurate and natural.

What are the most common grammar mistakes writers make?

Frequent errors include subject–verb disagreement, tense inconsistency, article misuse (a/an/the), pronoun–antecedent mismatches, homophone mix-ups (e.g., there/their/they’re), comma misuse, fragments, run-ons, wrong prepositions, incorrect word forms (adjective vs. adverb), double negatives, uncountable noun plurals (informations), dangling modifiers, faulty comparisons, its/it’s confusion, case errors with I/me, overused passive voice, less/fewer confusion, stray apostrophes for plurals, and unnecessary “that.” Knowing the categories makes it easier to spot and fix them.

How can I quickly check subject–verb agreement?

Isolate the true subject, ignore interrupting phrases, and make the verb match the subject’s number.

Wrong: The bouquet of roses <em>are</em> on the table. Right: The bouquet of roses <em>is</em> on the table. Rule: Singular collective subject + singular verb.

Watch out for misleading nouns after of (e.g., “list of items,” “group of people”). Also be careful with either/or and neither/nor: the verb agrees with the subject closest to it.

How do I keep my verb tenses consistent?

Choose a timeline for each sentence/paragraph and stay in it unless you have a clear reason to shift.

Past narrative: “I studied, moved, and adjusted.”
Present general truth: “Water boils at 100°C.”
Ongoing to now: Present perfect: “I have studied English for three years.”

If you change tenses, signal it with time markers: Now, At that time, Next year. Read aloud—shifts without a time cue often sound jarring.

When should I use “a,” “an,” and “the”?

a/an: first mention or non-specific item (I bought a phone).
the: specific, known, or unique item (the sun, the report we discussed).
Zero article with uncountables and plurals when speaking generally (Students need guidance; Information is vital).

Use an before vowel sounds (an hour), not just vowel letters.

How do I avoid homophone mistakes like “their,” “there,” and “they’re”?

Test replacements:

they’re → “they are” (if it fits, use they’re).
their → possession (belongs to them).
there → location or expletive subject (“There are…”).

Apply similar tests for your/you’re, its/it’s. Create a personal checklist for your top three homophone slips.

What’s the simplest way to fix comma mistakes?

Use commas after introductory elements, between items in a series, and before coordinating conjunctions that join two independent clauses.

Intro: After dinner, we studied. Series: We bought apples, oranges, and pears. Two clauses: I finished the draft, and I sent it.

Avoid random pauses. If removing a comma improves flow and meaning remains clear, remove it.

How can I spot and repair fragments and run-ons?

Fragment test: Does the clause have a subject and a finite verb, and can it stand alone? If not, attach it to a nearby sentence or supply the missing part.

Frag: Because I was tired. Fix: Because I was tired, I left early.

Run-on test: Are two independent clauses jammed together? Add a period, semicolon, or comma + coordinator.

Run-on: I went to the store I bought milk. Fix: I went to the store, and I bought milk.

Which prepositions are most commonly misused?

Some high-frequency pairs to memorize:

good at (not “good in” a skill): “She’s good at English.”
interested in, afraid of, rely on.
wait for (not “wait on” when the object is a bus/person).

When unsure, check trusted examples rather than translating literally from your first language.

How do I choose the correct word form (adjective vs. adverb)?

Adjectives modify nouns; adverbs modify verbs, adjectives, or other adverbs.

Adj + noun: a quick decision Adv + verb: decide quickly Wrong: She sings beautiful. Right: She sings beautifully.

Look for verb-linked descriptions (“perform <how?>”) to cue adverbs.

What is a dangling modifier and how do I fix it?

A modifier is “dangling” if it doesn’t clearly attach to the subject it intends to describe.

Dangling: Driving to work, the rain started. Fixed: While I was driving to work, the rain started.

Make the doer the subject right after the modifier, or reword the phrase.

How do I compare correctly (comparatives/superlatives)?

Use -er for short adjectives: faster, bigger.
Use more/most with longer adjectives: more effective, most efficient.
Never double-mark: not “more better” or “most fastest.”

For clarity, state the comparison set: “This method is faster than the previous one.”

How do I stop confusing “its” and “it’s”?

it’s = it is / it has. If you can replace with “it is/it has,” use it’s. Otherwise, the possessive pronoun is its (no apostrophe): “The company increased its revenue.” Create a quick substitution habit to prevent errors.

When is passive voice a problem?

Passive voice is useful when the actor is unknown or unimportant, but overuse makes prose vague.

Passive: The report was written by the team. Active: The team wrote the report.

Prefer active for accountability and energy. Keep passive for emphasis on the receiver or for scientific objectivity, but use sparingly.

Should I use “less” or “fewer”?

Use fewer for countable items (fewer books) and less for uncountable amounts (less time). Two exceptions: measurements and money often take less (less than 5 kilometers, less than $10).

How do I use apostrophes correctly?

Use apostrophes for possession and contractions, not for regular plurals.

Plural: Bananas (not Banana's) Possess.: The teacher’s book (one teacher), the teachers’ lounge (many). Contract: don’t = do not; it’s = it is/has.

When in doubt, ask: Is something owned? Or is it a shortened form?

What’s the best workflow to catch grammar mistakes fast?

Draft first: Get ideas down without over-editing.
Read aloud: Stumbles reveal fragments, run-ons, and comma issues.
One pass per error type: Do a dedicated sweep for articles, then for tenses, then for punctuation.
Search your personal “habit errors”: Scan for your top three mistakes (e.g., “it’s/its,” “less/fewer,” “there/their/they’re”).
Use tools—critically: Grammar checkers are helpers, not judges. Verify suggestions with rules and context.

Are double negatives always wrong?

In standard English, two negatives usually create a positive and read as nonstandard: “I don’t need no help” → means the opposite of what you intend. Use a single negative with an appropriate determiner: “I don’t need any help.” Some dialects permit double negatives for emphasis, but avoid them in academic and professional writing.

How do I handle uncountable nouns like “information” or “advice”?

Do not pluralize them and avoid “many.” Use “much,” “a lot of,” or partitives:

Wrong: many informations / advices Right: much information; a piece of advice; several pieces of equipment

Make a small list of common uncountables you use (information, advice, furniture, equipment, luggage, news, research).

When should I delete the word “that”?

Remove “that” if the sentence stays clear and grammatical:

Wordy: I think that you should apply. Tight: I think you should apply.

Keep “that” when it prevents ambiguity or misreading, especially with complex noun clauses.

What quick fixes can I apply right before publishing?

Change three passives to active (where appropriate).
Replace vague verbs (do, make, get) with precise ones.
Cut filler (really, very, actually, just, that) where meaning holds.
Confirm articles on first mentions; add the for known/specific items.
Run a targeted find/replace scan for your top homophone and apostrophe errors.

Can you give me a compact “grammar triage” checklist?

Subjects & verbs: Agreement correct? One timeline per paragraph?
Articles: Clear choice of a/an/the or zero article?
Punctuation: Fragments/run-ons fixed? Commas placed logically?
Forms: Adjective vs. adverb correct? Comparatives/superlatives clean?
Pronouns: its/it’s, your/you’re, case with I/me accurate?
Style: Prefer active voice; trim filler; ensure clarity.

Apply this checklist systematically, and your drafts will become clearer, more accurate, and more professional with every revision.