Savvas Learning
Pearson Longman: Sentence Resources for Writers: Commas
A grammar activity/assessment for the high school student on using commas correctly. With ten multiple choice questions that can be submitted to be scored and an essay question.
The Tongue Untied
University of Oregon the Tongue Untied: Punctuation: Comma
This site features a list of eleven simple rules for comma usage. Come and sharpen your grammar skills when you visit this educational resource.