山西省2017高考英语二轮复习专题训练：阅读理解（13）_高考复习指南

山西省2017高考英语二轮复习专题训练：阅读理解（13）

　　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 (分布) 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 a balanced spread age distribution. If the population naturally grows rapidly, the number of births greatly exceeds (超出) the number of deaths then as a total population increases proportion of 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 insufficient numbers of young people entering it to replace those who are leaving it. In that situation 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, finance must be available for that purpose. If the size of the workforce is small relative to the total population, then the government tax revenue (税收) is relatively low and either the government has less money available to it or the workforce members have to be taxed more heavily.