DWDM系统中λ2中心频率是（）。

光纤作为有线电视信号重要的传输介质，影响光纤通信系统传输距离和容量的最主要因素是（）。

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.

When loading or discharging dry mud or cement，crew members should use goggles and（）.

Effects which are dutiable or subject to prohibitions or restrictions should be declared in （）.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

WND是指在同一根光纤中同时传输多路不同波长电信号的技术。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。