Sentence Structure: Run-Ons, Fragments & Comma Splices
The ACT English section heavily tests sentence structure. A run-on sentence occurs when two independent clauses are joined without proper punctuation or conjunction. A comma splice is a specific type of run-on: two independent clauses joined with only a comma, which is insufficient. For example, 'The experiment failed, the researchers repeated it' is a comma splice. Fixes include: (1) adding a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so)—'...failed, but the researchers repeated it'; (2) using a semicolon—'...failed; the researchers repeated it'; (3) restructuring as a subordinate clause—'After the experiment failed, the researchers repeated it.' A sentence fragment lacks a subject, a verb, or a complete thought. 'Because the experiment failed' is a fragment—a subordinating conjunction like 'because' makes a clause dependent, requiring a main clause to complete it. On the ACT, the correct answer choice is always the most concise grammatically correct option.