Excellent companion for the BBG. This workbook is to be used as a test in order to hone your Greek skills. The book is compiled in a manner to maximize your study of Greek. The footnotes are very important. There is information in the footnotes that is not in the text. It is a must have item if you are serious about learning Greek.
If you buy the course book then you really need this book to help out and workout some of the exercises. And considering that the prices are so cheap compared to an actual course at a college or university where you would easily pay $200+ for these books you really can't go wrong.