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问题 多项选择题

关于通信建筑防雷接地系统的强制性规定有（）

A.通信建筑的接地系统应采用联合接地方式进行设计

B.机房的工作地、保护地、建筑防雷接地应采用联合接地，必须符合《通信局（站）防雷与接地工程设计规范》YD5098-2006的相关规定

C.综合通信大楼应采用联合接地方式，将围绕建筑物的环形接地体、建筑物基础地网及变压器地网相互连通，共同组成联合地网。局内设有地面铁塔时，铁塔地网必须与联合地网在地下多点连通

答案

参考答案：A, B, C

比较题

(1).氢氧化铝（）。
(2).米索前列醇（）。
(3).多潘立酮（）。
(4).西咪替丁（）。

A.抑制胃酸分泌

B.保护胃黏膜

C.两者皆可

D.两者皆不可
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填空题

The central problem of economics is to satisfy the people’s and nation’s wants. The problem we are faced with is that our (1) , here identified as money, are (2) . The only way we can resolve our (3) is to make choices. After looking at our resources, we must examine our list of (4) and identify the things we need (5) , those we can postpone, and (6) we cannot afford. As individuals, we face the central problem involved in economics — deciding just how to allocate our limited resources to provide ourselves with the greatest (7) of our wants.
Nations face the same problem. As a country’s population (8) , the need for more goods and services grows (9) . Resources necessary to production may increase, but there are (10) enough resources to satisfy the total desires of a (11) . Whether the budget meeting is taking place in the family living-room, in the conference room of the corporation (12) of directors, or in the chamber of the House of Representatives in Washington, the basic problem still exists. We need to find (13) 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 (14) abundance that economists had no concern about (15) of scarcity and what to do about it. Today many of these "free goods" are in (16) 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 pay for the producers’ extra costs, and (17) tax-payers who pay for the government’s involvement in cleaning the environment.
In the 1990s, almost all goods are (18) . Only by effort and money can they be (19) 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 (20) unlimited wants from limited economic goods, production leads to new problems in economics.
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