面板，机壳的烫印采用的材料是（）。它由三层组成，（）是聚酯薄膜，（）是金属箔，（）是

昆虫的繁殖方式包括（）。

A、两性繁殖

B、孤雌繁殖

C、孤雄繁殖

D、卵胎生

E、胎生

F、多胚生殖

瘦肉精，是一种非常廉价的药品，对于减少脂肪增加瘦肉作用非常好．瘦肉精有很危险的副作用，轻则导致心律不整，严重一点就会导致心脏病．下列关于两种常见瘦肉精的说法不正确的是（　　）

A．克伦特罗和莱克多巴胺均能发生加成、氧化、消去等反应

B．克伦特罗分子中所有的碳原子可以在同一平面内

C．克伦特罗和莱克多巴胺可以用FeCl3溶液鉴别

D．莱克多巴胺与足量Na₂CO₃溶液反应，生成物的化学式为C₁₈H₂₁NO₃Na₂

初始地籍测量是指在（）的基础上，进行的专业测绘工作。

A.初始权属调查

B.初始面积量算

C.初始土地登记

D.初始土地统计

如何灵活的运用“六特征”组卷法？

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.