ACT® · English: Sentence Structure and Formation
Comma Splices
A comma splice is two complete sentences joined by only a comma. The test wants you to catch it by checking whether both halves can stand alone, then fix it without changing the meaning.
A comma splice happens when two independent clauses, two word groups that could each be their own sentence, get joined by nothing but a comma. 'I studied all night, I still failed the quiz' sounds fine out loud because the ideas connect logically. But grammar doesn't ask whether the ideas connect; it asks whether the punctuation is strong enough to hold two sentences together. A comma alone isn't. That's why splices are easy to miss on a quick read and exactly why the test likes to hide them in smooth, sensible-sounding sentences.
The test for a splice is mechanical, not musical: cover the comma and read each side on its own. If both sides are a full sentence with a subject and a verb and no leftover connecting word, the comma is doing a job it can't do alone. You have four honest fixes, all of which keep the meaning unchanged: make it two sentences with a period, join the halves with a semicolon, add a coordinating conjunction after the comma (and, but, so, for, yet, or, nor), or turn one clause into a dependent one with a word like because, although, or when.
Watch how this connects to the next idea: a semicolon, not a comma, is what a word like however, therefore, or moreover needs in front of it, because those words describe a relationship between two sentences but don't have the grammatical strength to glue them together. 'The bus was late, however Maya waited' is still a splice with extra decoration. The fix is 'The bus was late; however, Maya waited.' Same logic, same four repair options, just a stronger mark doing the joining.
Key terms
- comma splice
- An error where two independent clauses are joined by only a comma with no conjunction.
- independent clause
- A word group with a subject and a verb that can stand alone as a complete sentence.
- conjunctive adverb
- A transition word like however, therefore, or moreover that shows a relationship but cannot join two sentences by itself.
- coordinating conjunction
- A short connecting word (and, but, so, for, yet, or, nor) that can join two independent clauses after a comma.
- dependent clause
- A clause starting with a word like because, although, or when that cannot stand alone as a sentence.
Watch it explained
- How it worksHow do you test one comma for a splice by covering it and asking whether both halves stand alone?
- Worked exampleWalk me through fixing 'The bus was late, Maya missed her audition' four ways without changing the meaning.
- Common mistakeWhy doesn't dropping in 'however' after the comma in 'The bus was late, however Maya waited' repair the splice?
Check yourself
End of topic.