OSPF协议中DR的作用范围是（）
A、整个运行OSPF的网络
B、一个area
C、一个网段
D、一台路由器
参考答案：C
Hong Kong was so busy over the Spring，Festval that all the hotel accommodation was full．She phoned several hotell but none of them had a()room．
A．cheap
B．nice
C．separate
D．vacant
功能凉血止血，外用治烫伤及脱发的药物是()
A．侧柏叶
B．槐花
C．大黄
D．石膏
E．生地
