I've got two more questions and a few reflections about OotP, and talking about it, I shall mention that it
killed me because I tried to read like 20 chapters in one day and I don't know how there're people who can do it, it's mental.
First: JK Rowling has a serious problem with numbers and quantities. And keep in mind that who says this is a girl who's always hated Maths and barely can find her house on the way back.
When Harry tells Umbridge that he had saw Voldemort killing Cedric, his mind says that he had never talked about that in front of 30 classmates before. But if I'm not wrong, in any moment she mentions that Gryffindors shared DADA with any other house, never minding that in the movies they do. And Gryffindor doesn't have that many students: they are five boys and three girls, unless JK doesn't considers necessary to inform readers that there're more students, but they can use another bedrooms and it's not necessary to be mentioned

So... are the other 22 students invisible, or they are ghosts, or it's just me who is awful with Maths or missed something?
Second: I think I know what's the veil for. It's said that there're stands around the platform where the veil is. Well, I came to the conclusion that it might be an ancient system of death penalty. Since the veil appears as having the property of ... dragging people to the beyond, and it doesn't hurt, I think that that's about it, and I suppose they have it in the Department of Mysteries to study why that happens, but of course they know what was the Death Chamber for.
Third: I wondered why didn't Dumbledore kill Voldemort when they fought; after all, he knew that he could kill him and that way they would have had more time to destroy the Horcruxes, right? But then I thought, maybe Dumbledore wanted to give Harry that chance, just like he did with the Philosopher's Stone; he knew that he had to tell Harry the truth after all, and that Harry wouldn't rest until killing Voldemort, and also he knew that there would have been something that would stop him because the prophecy said so. Or something.
And lastly... I think Harry was quite a prat in OotP, but... In some moments I can understand him: in the begginning, for example, I know quite well how he feels: somethimes I have felt like that, you feel that you're treated unfairly compared to your friends or close people, and you feel guilty for thinking that way, but you can't help it because... you know it's true! It's an horrible feeling, to think stuffs about your friends and hating yourself for that, but knowing at the same time that it's the very same truth. Also, Ron and Hermione were quite annoying all the time, but I can't say I can understand that because... well, most of the times it's me arguing with someone, so I'm never the Harry

On the other hand, Harry behaved like a stupid prat all the time; first, thinking that his friends didn't suport him. After all he went through with them, after having spent half a year mad with Ron, and knowing how awful it is to be alone, from all his childhood, it's extremely stupid to be mad at your friends all the time! And it's stupid not to trust Dumbledore just because he doesn't speak to you. I mean, even when Harry meant a lot to him, to Harry he still was his Headmaster, so... hello, what are you expecting? If he doesn't tell you his plans, he must have a reason, so stop behaving like a child!
Ok, and that's how my reading of Order of the Phoenix ended