When I taught at the University of Alabama, I would give a 100-question grammar, spelling, punctuation and diction exam to beginning writing students. The test was a difficult one, but students had to make at least a 75 on the exam to pass the beginning writing course offered by the College of Communication and Information Sciences. That exam is not available on this web site, but the study guide developed for it is. This is an excellent primer on the basic grammar and spelling rules and concepts that a student should know.