题目内容：

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 true，possible explanations could include the wide use of small electric and electronic devices，a reading-material explosion，a popular interest toward tight or pocket less 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 buildings，such as theatres and railway stations，you must go through a search or go bagless．The city has countless bag rules．It is hard to keep them 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 years 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 bags 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．”

1.How many reasons does the author list to explain the changes related to bags?

A. 2    B. 3    C. 4    D. 5

2.What do the bag rules in many public buildings require people to do?

A. Have their bags examined.    B. Pay for bringing in bags.

C. Leave the places bagless.    D. Use big clear plastic bags.

3.What is the purpose of the new rule at the New York Public Library?

A. To change people’s way of reading.

B. To prevent people stealing things.

C. To help people better use the library.

D. To stop people from bringing in dangerous things.

4.How is the effect of the new rule according to the librarian?

A. Excellent．    B. Satisfactory．    C. Harmful．    D. Limited．