（）是指在指导和影响下属的过程中，领导者所欣赏的各种行为模式。
A.领导行为
B.领导模式
C.领导理论
D.领导风格
参考答案：D
The man ______ was a friend of mine．
A．you just talked to
B．whom you just talked to him
C．who you just talked to him
D．which you just talked to
实际数据库系统中所支持的数据模型主要有______、网状模型、关系模型3种。
