Networks can be interconnected by different devices in the physical layer networks can be connected by (1) 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 (2) examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process in me network layer, we have routers that can connect two networks, If two networks have (3) 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 (4) . As an example, gateways between Internet e-mail and X.400 e-mail must (5) the e-mail message and change various header fields.

A．analyze

B．parse

C．delete

D．create

下列哪些症状或体征不符合DKA的表现（）

A.腹痛，食欲减退、恶心、呕吐

B.头痛、嗜睡、烦躁、呼吸深快，呼气中有烂苹果味

C.肌肉萎缩，疲乏无力，体重减轻，怕热出汗

D.严重脱水，尿量减少，皮肤弹性差，眼球下陷，心率快，血压下降。各种反射迟钝甚至消失，嗜睡以至昏迷