根据ISO对网络的分层协议，交换机和网桥工作在（）。
A.数据链路层
B.应用层
C.物理层
D.网络层
参考答案：A
根据语境，将单词补充完整。
1. The girl is a cl_ _er pupil
2. There are many boats on the r_v_r.
3. I will take my k_ _e on Tuesday.
4. What's the w_ _ther like today?
5. Beijing is bi_ _er than Tianjin.
