完形填空（第51～65题，每题1分，共15分） 阅读下面的短文，文中有15处空白，每处空白给出4个选项，请根据短文的内容从4个选项中选择1个最佳答案，涂在答题卡相应的位置上。
The Central Problem of Economics
The central problem of economics is to satisfy the people's and nation's wants.
The problem we are faced with is that our resources, here identified as money, are (51). The only way we can resolve our problem is to make choices. After looking at our resources, we must examine our list of (52) and identify the things we need immediately, those we can postpone, and (53) we cannot afford. As individuals, we face the central problem involved in economics——deciding just how to allocate (分配) our limited resources to provide ourselves with the greatest (54) of our wants.
Nations face the same problem. As a country's population .(55), the need for more goods and services grows correspondingly. Resources necessary to production may increase, but there are (56) enough resources to satisfy the total desires of a nation. Whether the budget meeting is taking place in the family living room, in the conference room of the corporation .(57) of directors, or in the chamber of the House of Representatives in Washington, the basic problem still exists. We need to find .(58) of allocating limited resources in order to satisfy unlimited wants.
A short time ago economists divided goods into two categories, free and economic. The former, like air and water, were in .(59) abundance that economists had no concern for them. After all, economics is the (60) of scarcity (匮乏) and what to do about it. Today many of these free goods" are (61) very expensive to use. Pollution has made clean air and water expensive for producers who have to filter their waste products, for consumers who ultimately (最终) pay for the producers' extra costs, and (62) taxpayers who pay for the government's involvement in cleaning the environment.
In the 1990s, almost all goods are (63). Only by effort and money can they be .(64) in the form people wish.
Meeting the needs of people and the demands from resources available leads to the basic activity of production. In trying to (65) unlimited wants from limited economic goods, production leads to new problems in economics.
51 A limited B unlimited C exhausted D abundant
52 A concepts B supplies C wants D resources
53 A those B Some C others D many
54 A expression B description C satisfaction D limitation
55 A climbs B extends C grows D raises
56 A always B sometimes C often D never
57 A management B function C board D company
58 A necessities B possibilities C needs D methods
59 A so B great C such D such an
60 A form B study C means D source
61 A in time B in practice C in reality D in turn
62 A then B also C for D with
63 A plentiful B scarce C poor D enough
64 A accepted B obtained C offered D discovered
65 A create B depress C restrain D meet