Today's lesson addressed essay writing for the AP exam, specifically how to add commentary to an essay. I explained the function of commentary -to explain the relevance of evidence , or to interpret the evidence in order to explain its significance . We then studied a sample student AP essay. Joshua did well in identifying the writer's use of commentary in the sample. We then applied the lesson to Joshua's essay on Faulkner's "A Rose for Emily" and discussed his use of commentary .