Cram It! O.W.L.에서 날아오르는 방법 O.W.L.을 위한 학습 가이드 벼락치기! How to Soar on Your O.W.L.s was a study guide intended to help fifth year students at Hogwarts School of Witchcraft and Wizardry prepare for their Ordinary Wizarding Level O.W.L.