|The plots may seem kind of familiar to readers of fantasy.
Book 5 is published by the Inner Mongolia People's Publishing Company. They at least changed the copyright page to have an English name, though it is not exactly colloquial English. A translated excerpt from chapter 1 is here, and no more is needed - at the end of chapter 1 Harry is turned into a hobbit, and starting from chapter 2 it is practically word for word identical with The Hobbit - really! Chapter-for-chapter is the same, right up to the end. It is very poorly written, and makes little sense.
6 and 7 are published by People's Literature Publishing Society. The copyright page is directly copied from Harry Potter and the Chamber of Secrets, so I had to translate the English names for myself. It also says that the works are copyright 1998, so apparently Ms. Rowling wrote 6 and 7 ahead of time.
I haven't had a chance to read them yet, but a quick glance shows that Gandolf is one of the main characters in both (maybe he was hired as the new Defense Against Dark Arts professor), and there doesn't seem to be a heck of a lot relating to the original books. Malfoy is listed in the cast of characters as "Harry's good friend", and "Harry's comrade in arms". In book 7 Harry is a 5th year student again.
It wouldn't surprise me at all if these are just later volumes from The Lord of the Rings. I haven't read any but The Hobbit recently enough to recognize the phrasing (especially in Chinese).
Here is the cover of the Chamber of Secrets, official edition. It also apparently is published by People's Literature Publishing Society, though to be fair the pirates who published 6 and 7 may have copied that name as well. The ISBN number for book 6 is the same as for Chamber of Secrets, and the ISBN number for book 7 is one higher.