{{Muggles' Guide to Harry Potter/Intermediate Spoiler}}
It is revealed later that Voldemort did indeed putcast a curse on the Defence Against the Dark Arts position. Ever since Dumbledore rejected him for the job, no teacher has remained in that position for more than one school year. Knowing this, it is curious as to why Snape continually applied for the position each year, or why Dumbledore chooses to appoint him now. It will be learned in the next book that Dumbledore, as a youth, was briefly attracted to the Dark arts when he befriended Gellert Grindelwald, who later became a notorious Dark Wizard that Dumbledore defeated in a famous duel. Dumbledore fully rejected Dark magic, though he never trusted himself to be in a position of power, choosing instead to teach at Hogwarts. One reason Dumbledore may have repeatedly denied Snape the position is because he similarly feared that Snape could be tempted by teaching a subject so closely linked to his Death Eater past. As it turns out, Snape will also only hold the position for the one year. Dumbledore, however, knows that his own life expectancy is less than a year at this point, and has, [[Muggles' Guide to Harry Potter/Books/Deathly Hallows/Chapter 33|as we see in the final book]], required Snape to promise that he will take over as Headmaster at Hogwarts after Dumbledore's death, to protect the school and the students.
Harry notes that Tonks' Patronus is "something large and hairy", and, reviewing recent events, decides that it must be related to Sirius' death, and that her sadness must be related to this as well. The reader may wonder why Tonks still seems depressed some months later, when Harry sees her in the halls at Hogwarts. In fact, her depression is the result of her repeated rejection by [[Muggles' Guide to Harry Potter/Characters/Remus Lupin|Lupin]], who apparently loves her but does not want to risk having children with her, and her Patronus has taken a wolf shape because of that.
