Run-on sentences occur when you have two or more independent clauses in a sentence that are not joined together properly. Once you know how to spot an independent clause and how to join them together, spotting and correcting run-on sentences is fairly easy.
Know the difference between and independent and dependent clause. Basically, a clause is a group of words containing a subject and a predicate. An independent clause is a clause that can stand alone as a complete simple sentence. For example: I went to the store. A dependent clause cannot stand alone, usually because it is preceded by a subordinating conjunction. For example: Because I was out of milk. A dependent and independent clause can usually be joined together in a sentence with just a comma: Because I was out of milk, I went to the store.
To spot a run-on, look for two independent clauses that are joined together with just a comma (which is called a comma splice). This is a run-on: I was out of milk, I went to the store.
To fix the run-on, you can split the clauses into two sentences: I was out of milk. I went to the store.
Another way to fix a run-on, is to use a conjunction: Because I was out of milk, I went to the store. You can also say: I was out of milk, so I went to the store.
The final way to fix a run-on is to use a semicolon, which exists specifically to join independent clauses together: I was out of milk; I went to the store.
David Boyles is a graduate student, teacher and professional writer. He has been teaching writing since 2005, while his own work has been featured in various publications and websites, including "Vegas Seven," "ArtsVegas," "AZ on the Scene Magazine" and the "Las Vegas Review of Books." Boyles holds a master's degree in English literature.