So which error types did they want to study first? Many students suggested we study passive voice because they see it all the time when typing at a computer but did not know what it meant. I told them that choice was interesting because passive voice first appears in our standards in seventh grade, so it would be a great unit to choose. They also proposed to study comma use because it appeared so often in their documents. I explained that we could focus our comma study on compound and complex sentence structure, one common area of difficulty for both student and adult writers. For the final unit I persuaded students to study subject-verb agreement based on how difficult these errors can be for the grammar checker to detect. It is also one of those difficult areas for both adolescents and adults.