Have you been writing papers all semester only to have them returned by your teacher with the comment "Run-On" scattered in the margins? You thought you learned how to fix those, but your teacher keeps taking points off your papers for repeat mistakes. Spotting and correcting run-on sentences is an easy task once you understand how to recognize complete thoughts, or independent clauses, in your writing. Also understand that run-on sentences are a common mistake when writers want to keep two or more ideas closely related. However, there is a correct way to punctuate closely related ideas.
Let's look at an example of a run-on sentence:
Many scientists believe outdooor cats are destructive cats kill songbirds, lizards, and endangered species of mice.
Why is this a run-on sentence? Because it contains two complete thoughts, or independent clauses, without punctuation. Do you see how there are two complete thoughts fused together?
Here is the first complete thought: Many scientists believe outdoor cats are destructive.
Here is the ...
This job defines and diagnoses Run-On Sentences.