Common Grammar Errors to Avoid

GCSE English Language · Spelling, Punctuation and Grammar

Common grammar errors to avoid

Accurate grammar is worth marks in every GCSE English writing task (and helps in Literature too). Here are the mistakes examiners see most often — and how to fix them.

Its vs it's

its = belonging to it (no apostrophe): the dog wagged its tail.
it's = it is / it has: it's raining.

Test: if you can say "it is", use it's.

Your vs you're

your = belonging to you: is this your book?
you're = you are: you're late.

There / their / they're

there = a place: sit over there.
their = belonging to them: their house.
they're = they are: they're happy.

Sentence errors

Comma splice: joining two full sentences with only a comma. It was late, everyone left. → Fix with a full stop, semicolon, or a conjunction: It was late, so everyone left.
Run-on sentence: several sentences with no punctuation between them — break them up.
Sentence fragment: an incomplete sentence missing a verb or subject.

Subject–verb agreement

The verb must match the subject:

The dog runs. (singular) / The dogs run. (plural)
Watch tricky ones: Each of the students is ready (each = singular).

Apostrophes for possession

Singular: add 's — the girl's coat.
Plural ending in s: add just ' — the girls' coats.
Never use an apostrophe for a simple plural (apple's for more than one apple is wrong).

Tense consistency

Keep your tense consistent — don't switch between past and present without reason.

Worked example

Correct this: "Their going to leave they're bags over there house."

"They're going to leave their bags over there... " (they're = they are, their = belonging, there... "house" here needs "their house") → They're going to leave their bags over at their house. ✓

Common mistakes

Mixing up its/it's, your/you're, there/their/they're.
Comma splices joining full sentences with a comma.
Apostrophes in ordinary plurals.

Exam tips

Proofread the last few minutes for these exact errors.
Test homophones with the long form (it is, you are, they are).
Check every sentence is complete and correctly joined.

Quick recap

Learn its/it's, your/you're, there/their/they're by testing the long form.
Avoid comma splices, run-ons and fragments; keep subject–verb agreement and tense consistent.
Apostrophes = contraction or possession, never plain plurals.