Abstract
The proportion of the U.S. population over 65 is growing and getting older, and the trend is expected to heighten in the early years of the 21st century.
摘要
美国65岁以上人口的比例正在增加且老龄化程度不断加深，预计这一趋势在21世纪初将更加明显。
The proportion of the U.S. population over 65 is growing and getting older, and the trend is expected to heighten in the early years of the 21st century.
美国65岁以上人口的比例正在增加且老龄化程度不断加深，预计这一趋势在21世纪初将更加明显。
Zotero 插件