A run on sentence happens when two or more independent clauses are joined incorrectly. An independent clause is a complete thought with its own subject and verb. The problem is not length. A sentence can be long and still be correct. The problem is the missing or incorrect connection between complete thoughts.
For example, this is a run on sentence: I was tired I kept working. Both parts can stand alone, but they are pushed together without proper punctuation or a joining word.
You can fix a run on sentence in a few clear ways:
- Use a period to make two separate sentences: I was tired. I kept working.
- Use a comma and a coordinating conjunction such as and, but, or, so: I was tired, but I kept working.
- Use a semicolon when the ideas are closely related: I was tired; I kept working.
A comma by itself is not enough. I was tired, I kept working. is called a comma splice, which is one type of run on error. When you proofread, check whether each side of the comma could stand alone. If both parts are complete thoughts, add the right connection.