Exactly identical to the book in terms of single page content, page numbering, and font type The ability to browse the book without connecting to the Internet The ability to save a tag at a specific page and refer to it later The program maintains a screen-lit mode for those who want to continue reading for a long time If the program closes at a specific page and opens it again, it will automatically go to the page at which it was closed An easy-to-access index of book contents Clear line and readability in both horizontal and vertical positions