Punctuation Guide

Why SPaG matters

In all writing tasks, marks are awarded for Spelling, Punctuation, and Grammar (SPaG). Accurate punctuation shows control and clarity of expression.

These are the most reliably winnable marks in the subject, because unlike ideas or creativity they do not depend on inspiration. A student who uses a semicolon correctly gets credit for it every time.

Key Punctuation Marks

Mark	Use	Example
Full stop .	Ends a sentence	She left. He stayed.
Comma ,	Separates list items; after fronted adverbials	Slowly, she turned.
Semicolon ;	Links two closely related independent clauses	It was cold; he shivered.
Colon :	Introduces a list or explanation	He felt one thing: fear.
Apostrophe '	Contraction (it's) or possession (John's)	The dog's lead.
Dash —	Adds emphasis or an aside; dramatic pause	He stopped — suddenly.
Ellipsis …	Creates suspense; shows a trailing thought	"But what if…"
Brackets ( )	Enclose extra information that could be removed	The house (empty for years) had a new door.
Speech marks " "	Enclose direct speech	"Wait," she said.

The comma splice — the most common error

Two complete sentences joined by a comma is an error, and it is the single most frequent punctuation mistake at GCSE.

Wrong: It was raining, we stayed inside.

Four correct fixes:

• Full stop — It was raining. We stayed inside.
• Semicolon — It was raining; we stayed inside.
• Conjunction — It was raining, so we stayed inside.
• Subordination — Because it was raining, we stayed inside.

The test: if the words on both sides of your comma could each stand alone as a sentence, a comma is not strong enough.

Semicolon versus colon

Students avoid both, which is a shame, because using either correctly is directly credited.

A semicolon joins two independent clauses that are closely related. Both sides must be complete sentences. The rain had stopped; the streets were still empty.

A colon introduces something — a list, an explanation, or an example. The part before the colon must be a complete sentence, but the part after need not be. She had one rule: never look back.

A simple way to remember it: the semicolon balances, the colon announces.

Apostrophes

Two jobs, and confusing them is heavily penalised.

Contraction — marking missing letters: don't, it's (it is), they're (they are).

Possession — showing ownership: the dog's lead (one dog), the dogs' leads (several dogs).

The traps worth memorising:

• its = belonging to it. it's = it is. The possessive has no apostrophe, which is the opposite of the usual rule
• your = belonging to you. you're = you are
• their / there / they're = belonging to them / place / they are
• Plurals never take an apostrophe: apples, not apple's

Dashes, brackets and ellipsis

Dashes are versatile and effective. A single dash creates a pause before an afterthought or a reveal; a pair works like brackets but with more emphasis. The door was open — she was certain she had locked it.

Brackets signal that the enclosed material is genuinely optional. If the sentence does not still work when you remove it, use commas or dashes instead.

Ellipsis creates suspense or a trailing thought, and is the mark most often overused in student writing. One in a piece is effective; five is a mannerism.

Punctuating speech

• Speech is enclosed in speech marks, and the punctuation goes inside them
• Use a comma before the closing speech mark when a reporting clause follows: "Wait," she said.
• Start a new paragraph for each new speaker
• Capitalise the first word of the speech

Common mistakes

• Comma splices — joining two sentences with a comma
• its / it's confusion, which is the most penalised apostrophe error
• Apostrophes in plurals — banana's for sale
• Overusing ellipsis and exclamation marks
• Not starting a new paragraph when the speaker changes

Exam tips

• Leave five minutes to proofread; most punctuation errors are visible on a second read
• Use one semicolon and one colon correctly in a writing task — both are credited and neither is difficult
• Read your work aloud in your head; you will hear missing full stops
• If unsure whether a comma is strong enough, ask whether both halves could stand alone

Key facts to remember

• SPaG marks are the most reliably winnable in the subject
• A comma splice is the most common error — check whether both halves are complete sentences
• The semicolon balances; the colon announces
• its is possessive and takes no apostrophe; it's means "it is"
• New speaker, new paragraph