问答题 DAC的转换过程主要有[填空(1)] 、[填空(2)] 和[填空(3)] 及[填空(4)] 四个过程。

单项选择题 WebSQL is a SQL-like(6)language for extracting information from the weB.Its capabilities for performing navigation of web(7)makes it a useful tool for automating several web-related tasks that require the systematic processing of either all the links in a(8), all the pages that can be reached from a given URL through(9)that match a pattern, or a combination of both. WebSQL also provides transparent access to index servers that can be queried via the Common(10)InterfacE.A.queryB.transactionC.communicationD.programming

单项选择题 Networks can be interconnected by different devices. In the physical layer networks can be connected by(31)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(32), examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process. In network layer, we have routers that can connect two networks. If two networks have(33)network layer, the muter 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(34). As an example, gateways between Internet e-mail and X.400 e-mail must(35)the e-mail message and change various header fields.A.reapersB.relaysC.packagesD.modems