Yes . . what can I say? It was expensive at first, and there were many copies in China.

Later, after the school strengthened management, it began to use genuine copies.

You're right. cie's teacher's manual recommended two or three textbooks.

Personally, I suggest buying those old books from Hong Kong on Taobao.

The new book revised this year is not easy to buy. You can go to the local Xinhua Bookstore for mail order. First, you can find the ISBN number of the book in cie, official website, and then ask them to send it to you from England. It may be examined at customs.

There seem to be textbooks on Wikipedia, too. Not very comprehensive. See for yourself.