ACT Punctuation Rules: Examples and Practice

What ACT punctuation questions actually test

The ACT English section puts you in the role of an editor. On paper, questions point to underlined text; online, they point to highlighted text. You choose the revision that works in the full passage. That means a punctuation answer must be grammatically correct and fit the surrounding sentence—not merely create a pause when you read aloud.

Use a clause-first punctuation decision map

A clause contains a subject and a verb. An independent clause also expresses a complete thought. Label the words on both sides of the punctuation before looking at the answer choices. This prevents commas, semicolons and colons from becoming a guessing contest.

Worked example: three ways to join two complete thoughts

Start with: The rehearsal ended late. The buses had already left. Both parts are complete sentences. You can keep the period, use a semicolon—The rehearsal ended late; the buses had already left—or show the relationship with a comma and conjunction—The rehearsal ended late, so the buses had already left. A comma alone would create a comma splice.

Worked example: why a colon is different

In Mina packed three supplies: tape, markers and scissors, the words before the colon form a complete sentence. What follows explains three supplies. By contrast, Mina packed: tape, markers and scissors is wrong because Mina packed leaves the verb without its object.

ACT comma rules: give every comma a job

A comma is not a general-purpose pause. On the ACT, it should perform a specific grammatical job. The fastest way to reject an answer is often to explain why its comma is present. If you cannot name the job, test the version without it.

The two-sided rule for nonessential information

If removable information interrupts a sentence, mark both boundaries: The mural, completed in June, covers the north wall. Deleting completed in June leaves The mural covers the north wall. One comma would open the interruption without closing it. The same matching rule applies to paired dashes.

Places a comma does not belong

• Between a subject and its verb: The stack of permission slips is on the desk.
• Between a verb and its object: The committee selected three finalists.
• Between two clauses unless a conjunction or another valid structure supports it: The rain stopped; the match resumed.
• Before every prepositional phrase: The class met in the library after lunch. needs no commas.

Semicolons, colons and dashes: know what comes before and after

Semicolon with however

Correct: The forecast predicted rain; however, the outdoor concert continued. Both clauses can stand alone. However is a transition, not a FANBOYS conjunction, so rain, however, the concert would still be a comma splice.

Colon or dash?

Both can introduce an explanation after a complete clause. A colon is the more neutral signal: The telescope revealed one surprise: a faint second ring. A dash gives the ending more emphasis: The telescope revealed one surprise—a faint second ring. First prove that the wording before the mark is complete; style comes second.

ACT apostrophe rules: possession, plurals and contractions

Before placing an apostrophe, decide whether the noun is possessive. Rewrite the relationship with of: the students’ proposals means the proposals of the students. Then decide whether the owner is singular or plural.

Use substitution for its and it’s

Replace the word with it is or it has. If the sentence still works, use it’s. If the word shows ownership, use its: The robot changed its route because it’s avoiding the stairs.

Common ACT punctuation mistakes and how to repair them

Notice that the repair is not always “add a better mark.” Sometimes the best revision removes punctuation. ACT’s official standards include deciding whether punctuation is needed at all and choosing marks that fit clause relationships.

ACT punctuation practice: 10 original questions

Choose the best version for each blank, then check your score. Explanations identify the sentence structure so you can reuse the rule. These are standalone teaching items; official ACT questions appear inside passages.

A four-step process for ACT English punctuation questions

1. Read beyond the underline. A missing partner mark or the end of a clause may sit several words away.
2. Label the sentence parts. Decide whether each side is an independent clause, a dependent clause, a phrase or a list.
3. Name the mark’s job. Joining clauses, introducing an explanation, setting off removable information and showing possession are different tasks.
4. Reread the full sentence. Confirm that the chosen answer preserves meaning and does not create a fragment, run-on or unnecessary break.

Use the no-punctuation choice as a real possibility, not a fallback. If the mark separates a subject from its verb, a verb from its object or a preposition from its phrase, removing it may be the precise correction. For passage-length timing practice, move from these original items to ACT’s free official practice.