That Mr. Testaverde talks so fast in his class. Students should just take a tape recorder to his class and then play the tape in slow-mo and he'll be talking normal. As for the grades, Kelly gets a C-, Lisa gets a D+, Jessie gets a B, Screech gets an A and Zack gets an F-. We don't find out what Slater gets but when he looks at his grade, he seems happy so he must've done alright.
One thing that's a little off is that Zack makes plans to take Screech to a race track on Saturday so they can use Screech's future vision to find out who will win each race and bet big on the winners. Now in real-life, what Zack's planning to do is illegal because it's against the law to bet on horse races if you're under 21.
Other than that, good episode.