以太网交换机和网桥工作在OSI模型的哪一层()。
A、数据链路层
B、传输层
C、网络层
D、会话层
参考答案:A
Large quantities of fish____caught in the Yellow Sea last year. [ ]
A. were
B. was
C. are
D. is
典型的腹外疝应由下列哪几部分组成()
A.疝门
B.疝外被盖
C.疝内容物
D.疝囊
E.以上均不是