ACT English: Stop Comma Splices and Run-Ons in Two Minutes

A comma splice joins two independent clauses with only a comma. Example: "The study showed results, the conclusion was clear." This is grammatically incorrect and appears on almost every ACT English test. The fix depends on your choice: (1) use a period to make two sentences, (2) use a semicolon to show they're related, (3) add a coordinating conjunction after the comma (and, but, or, so), or (4) turn one clause into a dependent clause. These four options cover every comma splice on the test, so you only need to recognize the error and pick the best fix.

Correct versions of the example: "The study showed results. The conclusion was clear." (period) or "The study showed results; the conclusion was clear." (semicolon) or "The study showed results, and the conclusion was clear." (comma+conjunction) or "Because the study showed results, the conclusion was clear." (dependent clause). All are grammatically correct.

To spot a comma splice in a passage, use this test: after you see a comma, ask yourself "Is there a subject and verb before the comma?" and "Is there a subject and verb after the comma?" If yes to both, and there's no coordinating conjunction, you have a comma splice. This test takes 5 seconds and eliminates guessing. Practice on sentences from the passages you're studying, not imaginary examples. Once you can spot the error in real ACT sentences, you'll automatically recognize when it appears under pressure.

Mark a few passages from a practice test and underline every comma. For each comma, ask the two questions. You'll find comma splices pop out immediately. This drill trains your eye to spot the error before you even read the answer choices.

Sentence 1: "The weather was cold, the team still practiced outside." Fix: Add "and" after the comma, or use a semicolon, or make two sentences. Sentence 2: "She wrote the report carefully, it contained no errors." Fix: These could become "She wrote the report carefully. It contained no errors." or "She wrote the report carefully; it contained no errors." Sentence 3: "The experiment failed, the scientist adjusted the method." Fix: "The experiment failed, so the scientist adjusted the method." (add "so") or use a semicolon. Notice that the best fix depends on the relationship between the two ideas: if one causes the other, use "so"; if they're equal, use a semicolon or period.

Now practice on five real ACT sentences from a practice test. Identify the comma splice, apply the test, and write two or three correct versions for each. This process embeds the skill into muscle memory.

Comma splice and run-on questions appear on every ACT English test, usually several times. They're considered foundational grammar errors, which means ACT tests them in multiple ways: as standalone errors, within longer passages, and in context. Mastering this one error family can earn you 3-5 extra points. Because the fix is mechanical and predictable, this is one of the highest-return grammar skills for your ACT prep effort.

Drill for 20 minutes over three days this week, focusing on identifying the error first, then choosing the fix. By test day, comma splices should feel obvious and easy.