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    Library of Congress (国会）is in the United States. This library is the largest library in the world. It is 3 stories high and the book shelves in it are 500 kilometers long.

    Resources

    The library has a large collection of resources like newspapers，magazines, CDs, videos and CD-ROMs. There are also many rooms for people to meet each other or listen to music. It also has a language learning center. It gets 2,000 questions a day, and some can be answered in a few minutes. Some need more time, sometimes a few months. All workers in the library use computers to help them.

    How to join

    If you are a middle school or above, then you can come to the library and fill in a form. Don't forget to bring your ID card. You must be an American and live in the United States.

    If you have time, come along to America and take a look around for yourself!

计算﹣$\frac{16}{3}÷\frac{4}{3}$（﹣$\frac{3}{4}$）的结果是____ 

材料一：去年上半年，全国2212万人因干旱而饮水困难，其中79%的人集中在江西、云南、贵州、广西等地。今年上半年我国南方又持续干旱，其中以江西、湖北等几省市尤为严重。

材料二：我国属于缺水国之列，人均淡水资源仅为世界人均淡水量的1/4，居世界第109位。在人均水资源方面，中国已被列入全世界13个贫水国家之一，而且水资源分布不均，大量淡水资源集中在南方，北方淡水资源只有南方淡水资源的1/4。据统计，全国600多个城市中有一半以上城市不同程度缺水，沿海城市也不例外，甚至更为严重。