通信技术的交换方式由传统的（）逐渐发展为分组交换、信元交换。

交换技术是通信网络发展的关键技术之一，最基础的三种交换技术不包括（）。

电力通信交换网交换机以四线连接时（包括2M数字中继线），电力通信交换网各交换机间的传输损耗为多少dB？

在程控交换系统中，进程之间的通信普遍采用的方法是（）。

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

程控数字交换机电话号码升位，则需要（）

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。