It is reported that bags are getting bigger all the time, and that there are more bags per person on the street today than at any other time in history. If this is ture, possible explanations could include the wide use of small electric and electronic gadgets (装置) , a reading-material explosion, a popular interest toward tight or pocketless clothing, or cheap bagmaking labor overseas. But , much as nature finds ways-such as disease-to control overpopulation, city life has thrown up impediments( 障碍 ) to bags. To enter many public building, theatres, ballparks, and perhaps even underground railway stations, you must go through a search or go bagless. The city has countless bag rules. It is hard to keep all straight, and you’re never sure, when leaving home for the day, whether it might be a bad idea to bring one along, Last week, the New York Public Library got in the game. Students, researchers, writers, historians, and anyone else who has got used over the year to treating the vast Rose Main Reading Room as an office or a reading room came up against a new rule. You are no longer allowed to bring a bag larger than eleven inches by fourteen inches into the library. If you walk in with one, you must leave it at the coat check. You may keep its contents with you, however, and the library provides big clear plastic for them. You return them when you come back for your own bag. What the library is trying to prevent, in this case, is people taking things out, rather than bringing things in. A librarian said on the second day, “It’s a big change for people who used to come and bring in half their flats. The people who use the library responsibly will continue to do so. The people who steal will continue to get away with it, if they really want to.” 题目:1、What does the writer mainly talk about?