Of all student usage "sins", writing run-on sentences is probably the most common, and one of the most grievous. Composition graders grit their teeth when they see this obvious sign of a lack of sentence control.

On multiple-choice assessments, including state assessments and the SAT, many questions are based on a student's knowledge of how to spot and avoid run-on sentences. This lesson gives numerous examples, plus examples of the three ways to fix a run-on sentence. Two practice worksheets are added after the lesson.