We know that we are getting even older, and that the nearer a society approximates to zero population growth, the older its population is likely to be - at least, for any future that concerns us now.

• 我们知道人类在日益变老，人口增长率接近于零的社会离我们越近，人口越可能呈老龄化的趋势，至少就与影响我们的未来来说是这样的。