Question type
Colons and dashes on the SAT
Use a colon only after a complete independent clause, to introduce a list, an explanation or an example: "two ingredients: sticky mucus and protein threads". A single dash can do the same job. A pair of dashes sets off an interruption, and it must close with a dash if it opened with one, never with a comma.
The choices offer a colon or a dash, often beside a semicolon and a comma. You decide whether what comes before is a complete sentence, and whether an interruption is being opened or closed.
College Board's question bank has 15 of these and rates 13 of them Hard.
- 15 in College Board's question bank, 87% rated Hard
- Reading it aloud misleads
Why students miss it
A colon after an incomplete clause, such as between a verb and its object.
Mismatched pairs: an aside opened with a dash and closed with a comma.
A semicolon where a colon belongs: a semicolon needs a full sentence on both sides, and a list is not one.
How to spot it
- A colon or a dash among the choices.
- A list or an explanation right after the blank.
- A dash earlier in the sentence, opening an aside.
The method
Colon or dash
Check what is before the blank, and whether a dash is already open.
- Complete clause, then a list or explanation
- colon (or a single dash).
- A dash opened an interruption earlier
- close it with a dash.
- Incomplete clause before the blank
- no colon.
Does reading it aloud help?
Colons, dashes, semicolons and commas all sound like the same pause.
- Cover everything after the blank. Is what remains a complete sentence?
- Look back for an opening dash; an aside must close the way it opened.
Two real questions
From the 1500prep bank, the way the app shows them. Answer first, then open the explanation.
When a shark or other predator seizes a hagfish in its jaws, the eel-shaped fish releases a slime that expands rapidly in the water, clogging the attacker's gills almost instantly. Biologists attribute this remarkably effective defense to two mucus and thousands of microscopic protein threads that unravel to form a dense net.
Which choice completes the text so that it conforms to the conventions of Standard English?
Show the answer and explanationThe answer: ingredients: sticky
In 1925, after measuring the spectral lines on hundreds of photographic plates, astronomer Cecilia Payne—then a doctoral student at that hydrogen and helium vastly outnumber all other elements in stars, a finding that overturned the prevailing belief that stars share Earth's makeup.
Which choice completes the text so that it conforms to the conventions of Standard English?
Show the answer and explanationThe answer: Harvard—concluded
Questions students ask
When do you use a colon on the SAT?
After a complete sentence, to introduce something that explains or lists what the sentence set up. What comes before the colon must be able to stand alone.
Can a dash and a comma go together around an aside?
No. An interruption opened with a dash closes with a dash; one opened with a comma closes with a comma.
Practise this type until it is automatic
Five more colon-and-dash questions, checked instantly, with every wrong choice explained. Free, no card.