宪法规定，父母与子女之间的义务是什么？
参考答案：
父母有抚养教育未成年子女的义务，成年子女有赡养扶助父母的义务。
When I try to understand ______ that prevents so many Americans from being as happy as one might expect,
it seemed to me that there are two causes. [ ]
A. why it does
B. what it does
C. what it is
D. why it is
在管理体制上，现代人力资源管理属于( )。
A．主动开发型
B．以事为中心
C．被动反应型
D．以人为中心
