Passage 13 In Hangzhou, borrowing books from the library is now as ____ (simply) as shopping online: click, pay and wait for delivery. The city’s public library recently launched a program on WeChat, ____popular Chinese messaging software, enabling its readers to check out books online and get them ____(deliver) to their homes at low prices. To enjoy the “Hangzhou enjoyable reading” service, one first needs to follow the library’s official WeChat account, ____provides a list of books. After picking books, borrowers are required ____(present) their information such as their library membership cards, cellphone numbers and so on. The selected items will be delivered by express within three days after payments. Each reader can borrow up to 5 books once and 20 books at most ____total. The books can be kept for up to 40 days. Readers now can borrow the library’s most popular books in this way. The online books will be renewed and enriched ____(gradual) according to reader’s borrowing habits and ____(prefer). At the end of December, the library’s old and classic books ____ (put) online too, making the total number of books available and bringing borrowers a lot of ____(convenient).