1. [多选题]When you compare the differences between half-duplex and full-duplex Ethernet, which of the following characteristics are exclusive to half-duplex? (Select two answer choices)
A. Half-duplex Ethernet operates in a shared collision domain.
B. Half-duplex Ethernet operates in an exclusive broadcast domain.
C. Half-duplex Ethernet has efficient throughput.
D. Half-duplex Ethernet has lower effective throughput.
E. Half-duplex Ethernet operates in an exclusive collision domain.
2. [单选题]IP地址为：192.168.50.70，掩码为：255.255.255.248，则该IP地址所在子网的子网号为（）
A. 192.168.50.32
B. 192.168.80.64
C. 192.168.50.96
D. 192.168.50.71
3. [单选题]访问控制列表分为标准和扩展两种。下面关于ACL的描述中，错误的是()。
A. 标准ACL可以根据分组中的IP源地址进行过滤
B. 扩展ACL可以根据分组中的IP目标地址进行过滤
C. 标准ACL可以根据分组中的IP目标地址进行过滤
D. 扩展ACL可以根据不同的上层协议信息进行过滤
