<p>Grammar books are hard to come across of. I’ve heard the Sparknotes Grammar/Writing guide is fantastic. I started reading some of it the other day and it covers A LOT of great information so try that maybe? After studying that thoroughly you should easily hit 630-700 in grammar. Then maybe go over old sections t o find tune a 700to higher. Its definitely possible because there guide hits the 7 major grammar rules as well as 4 less known (but also tested) rules. Also, its free :). Good luck!</p>