1 Will: You want me to replace Harry Potter? I'm not sure I'm up to that...
1 Hermione: So modest!
2 Ron: But all Harry's good at is getting into trouble. You know a lot more than he does, about a lot of things.
3 Ron: Muggle history, rhetoric, European literature, psychology, theatre, Greek mythology, poetry, English royalty...
4 Hermione: {making doe-eyes} Romance...
4 Ron: Steady on!

No, I don't know why they don't notice that this exchange student to Hogwarts has a full beard either.

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2016-07-15 Rerun commentary: Actually, given what we know about the Hogwarts curriculum, wizards and witches don't learn about any of those things, except maybe a smattering of Muggle history. All the classes at Hogwarts appear to be stuff related to various branches of magic. They don't seem to learn anything like basic arithmetic to count up galleons, sickles, and knuts; or geography; or languages; or economics; or art; or literature; or music - all of which would presumably be fairly useful topics to study, even if you can take care of many things with magic.