1. [单选题]介质100BaseT的最大传输距离是：()
A. 10m
B. 100m
C. 1000m
D. 500m
2. [单选题]Assuming you build networks to exact specifications, what is the recommended maximum length a 10BaseT cable can be before it has to be segmented or repeated?
A. 100 meters
B. 100 feet
C. 100 yards
D. 200 meters
E. None of the above
3. [单选题]通配符掩码和子网掩码之间的关系是（）。
A. 两者没有什么区别
B. 通配符掩码和子网掩码恰好相反
C. 一个是十进制的，另一个是十六进制的
D. 两者都是自动生成的
4. [多选题]Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)
A. Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B. Half-duplex Ethernet uses a loopback circuit to detect collisions.
C. A full-duplex Ethernet card allows 20Mbps for data transmission.
D. Full-duplex Ethernet makes use of two pairs of wires for data.
E. An Ethernet hub can operate both half and full duplex simultaneously.
5. [单选题]TCP23是（）协议端口号(port number)；UDP69是（）端口号(port number)；TCP80是（）端口号(port number)。
A. TELNET FTP HTTP
B. FTPT FTP HTTP
C. TELNET TFTP HTTP
D. TELNET DNS HTTP
