Common English Grammar Mistakes (and How to Fix Them)

Some English mistakes are so common that even native speakers make them. The good news is that most come down to a handful of word pairs and rules. Learn these and your writing will instantly look more careful and professional.

1. Your vs. You’re

Your shows possession; you’re is short for you are. If you can replace it with “you are,” use you’re.

✅ You’re going to love your new book.

2. Its vs. It’s

This trips up almost everyone. It’s = it is or it has. Its = belonging to it. The apostrophe means a missing letter, not possession.

✅ It’s clear the dog wants its food.

3. There, Their, They’re

• There — a place: Put it over there.
• Their — possession: Their house is big.
• They’re — they are: They’re late.

4. Fewer vs. Less

Use fewer for things you can count, and less for things you can’t.

✅ Fewer cars, less traffic.

5. Then vs. Than

Then is about time or sequence. Than is used for comparisons.

✅ She is taller than me, and then she grew even more.

6. Affect vs. Effect

Affect is usually a verb (to influence). Effect is usually a noun (the result). Trick: Affect = Action.

✅ The weather affects my mood; the effect is obvious.

7. Subject–verb agreement

A singular subject takes a singular verb. Long sentences make this easy to lose track of.

❌ The list of items are on the desk.
✅ The list of items is on the desk. (the subject is “list,” not “items”)

8. Apostrophes for plurals

Plurals almost never take an apostrophe. Apples, not apple’s — unless you mean possession (the apple’s color).

The fastest way to catch these

When you’re unsure, run the sentence through an analyzer that breaks down each word and flags how it’s being used. Seeing the part of speech for every word makes these mistakes obvious — and you learn the rule, not just the fix.