Reading and Writing · 23 · Punctuation · Free
Half-Stop Punctuation
Notes
Key points
- Half-stops: colon (:) and single dash (—). Both need a complete sentence before them.
- What comes after can be a word, a list, a phrase or a full sentence.
- Use them to introduce: an explanation, an example, a list, a reveal.
- Two dashes act like two commas: they wrap extra information.
- Never put a colon right after a verb or a preposition.
Rules
Complete sentence before a colon, always.
She packed one thing: a camera.
She packed: a camera.
A single dash works like a colon.
The result surprised everyone — the control group won.
Paired dashes must match; don't mix a dash with a comma.
The river — swollen by rain — flooded the road.
The river — swollen by rain, flooded the road.
Common traps
- Colon after “such as”, “including” or a verb — always wrong.
- Picking the colon just because a list follows; check the part before it first.
- Mixing one dash and one comma around the same extra phrase.
SAT tip
Cover the part after the punctuation: if what's left can stand alone as a sentence, a colon or dash works.
Test yourself
10 official SAT questions on Half-Stop Punctuation, easiest first.