Networks can be interconnected by different devices. In the physical layer, networks can be connected by (41) 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 (42) , 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 (43) network layer, the router may be able to translate between the packet 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 (44) . As an example, gateways between Internet E-mail and X.400 E-mail must (45) the E-mail message and change various header fields.

A．special

B．dependent

C．similar

D．dissimilar

根据刑事诉讼法的原理和有关规定，逮捕应符合“有证据证明有犯罪事实”的法定证据条件。这一法定证据条件的完整、准确含义是指（）。

A．有证据证明发生了犯罪事实并有证据证明犯罪事实系该犯罪嫌疑人实施

B．证明犯罪嫌疑人实施犯罪行为的证据已有查证属实

C．上述A、B两项条件至少应具备其中的一项

D．上述A、B两项条件应同时具备