新民主主义文化中居于指导地位的是A． * * 主义思想 B．民族的形式 C．科学的内容 D

断肢在行再植手术之前应保存在

A．乳酸林格液

B．75%酒精

C．10%福尔马林溶液

D．用无菌或清洁敷料包扎后干燥冷藏

E．置于37℃恒温箱中

在公正的内容原则中，进行公正分配的根据不包括

A．根据个人能力

B．根据对社会的贡献

C．根据个人的地位

D．根据科研价值

E．根据个人需要

(8分)右图是血液循环和气体交换示意图，请据图回答：

（1）图中的5所指的是      ，内流     血。图中7所指的是      ，内流    血。

（2）血液由2射出，流经5、6到3的循环途经叫      ；

（3）由M到N处，血液成分发生的变化是           。

（4）心脏结构中心壁最厚的是[ ]      ，它是    循环的起点.

Workforce is defined as the total number of people who are available to work and earn incomes. The definition includes everyone who is employed or seeking paid employment, so it includes employers and the self-employed.

Although the size of the workforce depends a great deal on the size of the total population, there are several other influences which also affect it. The age distribution of the total population has a very marked effect on the available workforce. If the population has a high proportion of very young people or of those too old to work, then the available workforce would be lower than if there were an evenly spread age distribution. If the population grows rapidly from natural increase, i.e., the number of births greatly exceeds the number of deaths, then as the total population increases, the proportion in the workforce declines

Sometimes a population is described as aging, which means that the birth rate is either falling or growing very slowly, and as people retire from the workforce, there are not enough young people entering it to replace those who are leaving it. The population is top-heavy with older people. So the percentage of the population in the workforce declines when there is either a rapid increase in births or a falling birth rate.

The age distribution of the population has several important effects on the economy. If the population is aging and there is an increase in the number of people retiring without a corresponding increase in the number entering the workforce, this raises the problem of the ability of the economy to provide a reasonable level of social services to the retired group. If the aged are to be cared for in special homes or hotels, finances must be available for that purpose. If the size of the workforce is small relative to the total population, then the government tax receipts are relatively low and either the government has less money available to it or the workforce members have to be taxed more heavily.

The last paragraph focuses on ().

A. the factors that influence the workforce structure

B. the importance of workforce distribution to the economy

C. the relationship between age distribution and economy

D. the influence of population growth on the national economy

金属导体的电阻与导体（）有关。

A、长度；

B、截面积；

C、电阻率；

D、材料