Twenty copies. According to the query of Binjiang District Library, Binjiang District Library borrows 20 books at a time, with a borrowing period of 40 days, and can renew them once during the borrowing period, with a renewal period of 15 days. Binjiang District Library was opened to the public on February 20 15 and February 20 15, with a building area of 7,000 square meters, three floors and 875 reading seats. Readers use computers 16. It is the first professional theme library in Hangzhou focusing on science and technology and reading experience.