根据社会组织成员之间关系的性质把社会组织进行分类的是( )。

A．功能原则

B．控制原则

C．结构原则

D．政治组织

Mobility is one of the characteristics often （） executives, and they must accustom themselves to moving quite regularly.

A. demanded of

B. asked for

C. expected from

D. called for