A:有利于解决发达国家的老龄化问题
B:可能促进发达国家的老龄化问题
C:使得发达国家经济发展缓慢
D:使得发达国家城市人口大量减少
—Oh, it's me! This photo when I was five years old.
— So many problems! I'm too tired.
— You should try ________ them by yourself.
公共设施的主要提供者和管理者是 ( )