单选题 Labor force is defined as being the total number of people who are available to work and earn income. This definition includes everyone who is employed or seeking paid employment, so it includes employees and the self-employed. Labor is one of the country's resources which can be combined with other resources to produce the goods and services required by the community.
Though the size of the workforce relies greatly on the size of the total population, there are several other aspects 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 m 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 a total population increase 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 inadequate numbers of young people entering it to take place of 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 influences 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 hospitals, finance 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.

单选题 Labor force is composed of ______.

A、 people who are available to work and earn income
B、 self-employed people only
C、 only those who are looking for an employment
D、 only the employees

【正确答案】 A

【答案解析】细节题。文章第一句话即对labor force(劳动力)这一术语的定义进行了说明：．．．who are available to work and earn income，即它包括的是可以工作、获得收入的人，因此本题答案为[A] 。

单选题 The factor which does NOT influence the size of the workforce is ______.

A、 the size of population
B、 age distribution of the population
C、 national economy
D、 natural increase

【正确答案】 C

【答案解析】细节题。文章第二段论述的是影响劳动力规模的几种因素。其中第一句中提到了the size of the total population([A] )，第二句提到了the age distribution([B] )，最后一句话中提到了natural increase ([D] )，它们都会影响劳动力的规模。只有[C] 没有提及。

单选题 The conclusion which can be drawn safely from the second paragraph is that ______.

A、 a population growth from natural increase leads to a greater proportion of the workforce
B、 a large population does not necessarily mean a higher proportion of workforce
C、 the larger the number of the aged in a population, the higher the proportion of the workforce
D、 if the population has an evenly spread age distribution, the workforce will be lower

【正确答案】 B

【答案解析】分析推理题。第二段后两句指出，如果人口中小孩和老人所占比重很大，那么可用的劳动力就会相对较少；如果人口自然增长超过死亡人数，那么劳动力在总人口中所占比重就会下降。由这两句即可推知，总人口多并不一定就意味着劳动力多，故选[B] 。

单选题 When a population is said to be aging, ______.

A、 more people are retiring than people entering the workforce
B、 the birth rate is growing rapidly
C、 ]there is an oversupply of workforce
D、 young people outnumber old people

【正确答案】 A

【答案解析】细节题。第三段第一句对“人口老龄化”这一术语进行了说明，由其后一分句：and as people retire from the workforce．．．who are leaving“可知它指的是退休的人数超过就业的人数，因此答案是[A] 。

单选题 The population which is top-heavy with older people poses a problem to ______.

A、 the government
B、 the economy
C、 the workforce
D、 all of the above

【正确答案】 D

【答案解析】细节题。本题为细节比对题。文章最后一段论述了人口老龄化对经济的影响，将四个选项与该段进行对照，发现[A] 、[B] 、[C] 三项都会受到老龄化的影响，因此答案是[D] 。