Demographers (人口統計學者) reckon that three-quarters of humanity could be city-dwelling by 2050, with most of the increase coming in the fast-growing towns of Asia and Africa.
出自-2013年6月閱讀原文
Ronald Lee, director of the Centre on the Economics and Demography of Ageing at the University of California, Berkeley, puts it briefly and clearly: "We don't really know what population ageing will be like, because nobody has done it yet.
出自-2010年12月閱讀原文