1. [多选题]Why is full-duplex Ethernet superior to its single-duplex counterpart? (Select two answer choices.)
A. It uses inexpensive hubs
B. It operates without collisions
C. It operates on switches
D. It provides faster data transfer
E. It utilizes fewer wiring pairs
2. [单选题]在OSI七层模型中，介质工作在哪一层()
A. 传输层
B. 会话层(session layer)
C. 物理层
D. 应用层
3. [单选题]在OSPF的完全存根区域中，使用以下哪种LSAType报文或其它方式与区域间通信：（）
A. LSAType1.2
B. LSAType3
C. LSAType4
D. 默认路由：0.0.0.0
