Why can't e-books of People's Education Publishing House turn pages?

In the past, I noticed that the last string of numbers on the website decreased with the increase of pages. So after I couldn't turn the page, I turned the page by modifying the website. If you want to turn the page, subtract one digit from the last string of numbers in the URL. For example, the website of the first lesson of 8th grade language in junior middle school is/czyw/jszx/tbjxzy/dzikb/bs/201008/t20100825 _ 729040.htm. If you want to turn pages, you can change the website to /czyw/jszx/tbjxzy/dzikb. This method is universal throughout the website. I feel a little troublesome. Hmm. How interesting