There are generally three ways to identify the authenticity of books. One is whether there is a watermark in the book. If the watermark is blurred, the book is pirated. The second is the printing quality. The printing quality of genuine books is generally good, which is manifested in clear handwriting, consistent ink and good paper. Another is the price. Generally speaking, the discount of teaching materials for vocational examinations is very small. If there is a discount on genuine books, the minimum discount is 8.5%. Below this price, be careful.

As for what I bought online, it is probably pirated. Although some online bookstores are also 10% off or genuine, they are not necessarily genuine. If you don't often deal with some pirated books, you can't tell whether they are pirated or genuine. There are two places to buy genuine books, one is the customs, and the other is the Xinhua Bookstore where you registered. Other places may be pirated.