常在龋好发部位,形状和程度与牙菌斑有关 A.脱矿性斑 B.色素附着 C.四

题型:单项选择题

问题:

常在龋好发部位,形状和程度与牙菌斑有关

A.脱矿性斑
B.色素附着
C.四环素牙
D.釉质钙化不全
E.氟牙症

考点:口腔执业医师口腔执业医师65
题型:单项选择题

下列说法不正确的是[ ]

A.一个数与它的倒数之积是1  

B.一个数与它的相反数的商为-1  

C.两个数的商为-1,则这两个数互为相反数  

D.两个数的积为1,这两个数互为倒数

题型:单项选择题

关于员工关系和员工关系管理的说法,正确的是()。

A.员工关系管理是人力资源管理的组成部分 

B.员工关系是员工之间的各种法律的、情感的和理论的联系 

C.员工关系管理以员工与组织签订契约为管理的起始点,以契约解除或终止为管理的终点 

D.员工关系管理是一种双向管理行为

题型:单项选择题

司机报单上的机车所属局、段名、机车型号、车号、年、月、日,乘务员姓名及出勤时分由()填记。

A.司机

B.学习司机

C.机车调度员

D.调车长

题型:单项选择题

最长寿的动植物分别是什么?

题型:单项选择题

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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