He spent July and the first half of August reviewing the basics of his Hogwarts classes until the tutors – two wizened old sisters who split the subjects between them – were satisfied with his proficiency in everything except potions, which required a further week and a half of intensive tutoring. Harry took no responsibility, and blamed Snape entirely. They spent the end of August preparing him for the OWL exams he’d take in his upcoming 5th year.