关于阿米巴肝脓肿和细菌性肝脓肿的鉴别诊断,最重要的指标是()
A.起病缓急
B.脓液的颜色
C.毒血症状轻重
D.脓肿的个数和大小
E.局部症状的轻重
参考答案:B
Networks can be interconnected by different devices. In the physical layer, networks can be connected by (11) or hubs, which just move the bits from one network to an identical network. One layer up we find bridges and switches, which operate at data link layer. They can accept (12) ,examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have (13) network layer, the router may be able to translate between the packer formats. In the transport layer we find transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message (14) . As an example, gateways between Internet e-mail and X.400 e-mail must (15) the e-mail message and change various header fields.
11()
A.repeaters
B.relays
C.packages
D.modems
口岸是供人员、货物、物品和交通工具出入国(关、边)境的()。
A、港口
B、机场
C、车站
D、跨境通道