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来源:雅诚德英语网
It was once a rule of demography that people have fewer children as their countries get richer.
人口统计学上曾经有一条规律:国家越富裕,人们就越少生育。
It was once a rule of demography that people have fewer children as their countries get richer.
人口统计学上曾经有一条规律:国家越富裕,人们就越少生育。