听力原文：Narrator Listen to part of a lecture about libraries. Professor The earliest

libraries existed thousands of years ago in China and Egypt where collections of records on tablets of baked clay were kept in temples and royal palaces. In the western world, libraries were first established in Ancient Greece. For example, Aristotle once had a research library in the 3rd century BC. The first library in the Unites States was a private library, which could only be used by authorized readers. In 1633, John Harvard gave money and more than 300 books to a newly-established college in Massachusetts. In return for his generosity, the legislature voted the school to be named Harvard College. The librarian there set rules for the new library. Only college students and faculty members could use the books No book could be lent out for more than one month. The earliest public library was established in Philadelphia in 1731. Although this library was open to every one, all readers had to pay a membership or subscription fee in order to borrow books. Very few subscription libraries exist today. Some book and stationary stores maintain small rental libraries, where anyone may borrow books for a daily charge. The first truly free public library that circulated books to every one at no cost, was started in a small New England town in 1833. Today, there are more than 7 000 free public libraries throughout the U. S. They contain about 160 million books which are circulated to over 52 million readers. Historically, the major purpose of free public libraries was educational. They were expected to provide adults with the opportunity to continue their education after they left school. So the function of public library was once described as "less reservoir than a fountain". In other words, emphasis was to be placed on wide circulation rather than on collecting and storing books. Over the years public library services have greatly expanded. In addition to their continuing and important educational role, public libraries provide culture and recreation, and they are trying to fill many changing community needs Most libraries offer browsing rooms where readers can relax on comfortable chairs and read current newspapers and magazines Many also circulate music records Library programs on films, lectures, reading clubs, and concerts also attract library users. In addition to books, records, periodicals, and reference materials, libraries provide technical information such as books and pamphlets on gardening, carpentry and other specialized fields of interests. The largest public library in the U. S. is the Library of Congress. It was originally planned as the reference library for the federal legislature. Today, in addition to that important function, it serves as the reference library for the public, and sends out many books to other libraries on the inter-library-loan system. Unlike free pubic libraries, which are open to everyone, private libraries can be used only by authorized readers. Many industrial and scientific organizations and business firms have collections of books, journals and research data for their staff. Several private historical associations have research collections of special interest to their members. In addition, many elementary and secondary schools operate libraries for use by students and teachers. Prisons and hospitals maintain libraries, too. The largest and most important private libraries are operated by colleges and universities. These libraries are used by students, faculty members, and occasionally by visiting scholars. Many universities have special libraries for research in particular fields, such as law, medicine and education. Recent surveys report that mere than 300 million books are available in these academic libraries and they are regularly used by over 8 million students. Now get ready to answer the questions. You may use your notes to help you answer. 17. What is the main purpose of the talk？ 18. Who drew up the rules for the first private library in the U. S. ？ 19. Why was the earliest public library also called a subscription library？ 20. What are the three purposes of free public libraries？ 21. What is the largest public library in the United States？ 22. What does the speaker imply when he says this？ Professor Unlike free pubic libraries, which are open to everyone, private libraries can be used only by authorized readers. Many industrial and scientific organizations and business firms have collections of books, journals and research data for their staff.Narrator Listen to part of a lecture about libraries. Now get ready to answer the questions. You may use your notes to help you answer.

What is the main purpose of the talk？

A．To introduce categories of books in the U. S. libraries.

B．To demonstrate the importance of the U. S. libraries.

C．To explain the roles of different U. S. libraries.

D．To define the circulation system of the U. S. libraries.