1. If there is only one book stand, put a row of books between the bookshelf and the book stand. On top of a row of books, several large books can be placed flat, and on the other side of the book stand can also lean a few books.
2. Knowledge of the book's force: The book has downward pressure on the book; the book has upward support for the book, and the two forces are interacting forces. Book stands and desktops also have mutual pressure.
3. Book stands are usually sold as a pair (two). The reason is that a book stand must be clamped on both sides when it is used. In special cases, such as leaning against a wall, you can use the wall as a side. Used at the other end).