Colons: After a Complete Sentence

American Diploma › Digital SAT Reading and Writing — Complete Course

What this question type tests

Colon questions are tested in the Boundaries skill of the Standard English Conventions domain (about 26% of the scored Reading and Writing questions, 11–15 questions). A colon can link two clauses or introduce a list or a supplement, so it appears in many boundary questions — sometimes as the key, very often as a trap placed right after a verb or after “such as.”

The format: a short passage (25–150 words) with a blank and the stem “Which choice completes the text so that it conforms to the conventions of Standard English?” The choices often show four marks in the same place — “ingredients;” / “ingredients:” / “ingredients,” / “ingredients” — and you must know exactly what a colon is allowed to do.

The rule: complete sentence first

The teacher's rule: a colon comes after a complete sentence (an independent clause) and introduces a list, an explanation, emphasis or extra information about what came before it.

The period test before every colon: stop at the colon and read only the part before it. Could a period go there? If yes, the colon may be correct. If no, the colon is wrong — whatever comes after it.

Where a colon is never allowed

How to make the left side complete: add a noun that names what is coming — “three things,” “the following students,” “several events,” “one reason.” Words like the following and as follows are made for colons: “The rules are as follows: …” ✓.

• ✗ The festival includes: a poetry contest, a film night, and a book fair.
• ✓ The festival includes several events: a poetry contest, a film night, and a book fair.
• ✓ The festival includes a poetry contest, a film night, and a book fair. (no colon at all)
• ✗ The festival includes several events, including: a poetry contest … (never after “including”)

Colon between two complete sentences

A colon can join two independent clauses when the second explains, proves or gives the result promised by the first: “The researcher's conclusion was simple: the birds were following the river.” The second clause answers the question the first one raises (What was the conclusion? Why? What exactly?).

• ✓ The village had a serious problem: its only well had dried up.
• ✓ The plan worked: within a year, the canal was full of fish again.
• ✗ The village had a serious problem, its only well had dried up. (comma splice)
• ✗ The village had a serious problem: because its only well had dried up. (dependent clause after the colon — no explanation sentence)

If two complete sentences are only side by side (two parallel facts) and the choices also offer a semicolon or a period, those are the safer choices. The test will not offer a correct colon and a correct semicolon as two different answers — if both appear, one of the choices has another error.

Colon, dash or semicolon?

Colons and single dashes overlap: both can introduce a final word or phrase that gets emphasis. Because both are correct, a question normally offers only one of them. If a colon and a dash both appear in the choices, the other words in those choices will decide.

Worked examples

Worked example 1 — colon after an incomplete clause

Text: Members of a desert research expedition must carry everything they need for ten days, because there are no shops for hundreds of kilometers. The expedition's supply list included ______ water filters, solar lamps, and several kilograms of dried dates.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) included:
• B) included
• C) included;
• D) included—

Answer: B

• A) ✗ Wrong: “The expedition's supply list included” is not a complete sentence — the verb has no object. A colon cannot follow it.
• B) ✓ Correct: No punctuation: the verb “included” goes straight to its object, the list.
• C) ✗ Wrong: A semicolon needs complete sentences on both sides; neither side is one.
• D) ✗ Wrong: A dash cannot separate a verb from its object.

Worked example 2 — colon for an explanation

Text: The bus drivers' strike had been expected to last for weeks. Instead, it ended after only two days for one simple reason ______ the city agreed to all of the drivers' demands.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) reason; because
• B) reason,
• C) reason:
• D) reason, which

Answer: C

• A) ✗ Wrong: A semicolon cannot come before a dependent clause, and the left side promises a reason that should be stated directly.
• B) ✗ Wrong: A comma here joins two independent clauses: comma splice.
• C) ✓ Correct: The left side is complete and promises “one simple reason”; the colon introduces the clause that gives it.
• D) ✗ Wrong: “Which the city agreed to …” does not explain the reason and makes the sentence ungrammatical.

Worked example 3 — the “such as” trap

Text: Fertile soil and water from the river make the north of Egypt one of the country's richest farming regions. Several crops ______ rice, cotton, and wheat, are grown in large quantities in the Nile Delta.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) , such as
• B) such as:
• C) , such as:
• D) : such as

Answer: A

• A) ✓ Correct: “Such as rice, cotton, and wheat” is extra information here, opened by a comma and closed by the comma after “wheat.” No colon is needed after “such as.”
• B) ✗ Wrong: Never a colon after “such as,” and the extra information is closed by a comma but never opened.
• C) ✗ Wrong: Opening comma ✓, but a colon after “such as” is never allowed.
• D) ✗ Wrong: A colon after “Several crops” — not a complete sentence.

Worked example 4 — colon for emphasis

Text: The small engineering team had worked in a borrowed garage for three years, often without pay. Last month, they finally had what they had been working toward ______ a working prototype of their water-cleaning machine.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A) toward; a
• B) toward, it was a
• C) toward a
• D) toward: a

Answer: D

• A) ✗ Wrong: A semicolon needs a complete sentence after it; “a working prototype …” is a phrase.
• B) ✗ Wrong: “It was a working prototype” is an independent clause joined by only a comma: comma splice.
• C) ✗ Wrong: With no mark, “what they had been working toward a working prototype” runs together and becomes confusing.
• D) ✓ Correct: The left side is complete, and the colon introduces the phrase that names what they achieved — emphasis.

Practice

Ten original Digital SAT-style questions on colons. Read the left side of the blank first.

All pages in this course

Start here

• The Digital SAT: Complete Overview
• Time Strategy and How to Attack Every Question

Craft and Structure

• Words in Context
• High-Value Vocabulary for SAT Reading and Writing
• Text Structure and Purpose
• Cross-Text Connections

Information and Ideas

• Central Ideas and Details
• Command of Evidence: Textual
• Command of Evidence: Quantitative
• Inferences

Standard English Conventions

• Sentence Boundaries
• Extra Information: Commas, Dashes and Brackets in Pairs
• Commas: Introductions, Lists, Adjectives — and When NOT to Use One
• Semicolons: Joining Two Complete Sentences
• Colons: After a Complete Sentence
• Dashes — and Choosing Between , ; : —
• Subject–Verb Agreement
• Pronoun–Antecedent Agreement, Clarity and Consistency
• Pronoun Case and Sound-Alike Pronouns
• Verb Tense and Aspect
• Verb Finiteness: Gerunds, Participles and Infinitives
• Dangling and Misplaced Modifiers
• Parallel Structure
• Faulty and Logical Comparisons
• Plurals and Possessives

Expression of Ideas

• Transitions
• Rhetorical Synthesis (Student Notes)

Full practice tests

• Digital SAT Reading and Writing — Practice Test 1
• Digital SAT Reading and Writing — Practice Test 2
• Digital SAT Reading and Writing — Practice Test 3