（）, 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 （）.

什么叫做介质、介质损失及介质损失角？

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

介质损失角正切值tanσ的测量通常采用（）。

关于介质损失角的正切tanσ的叙述正确的是（）。

介质损失主要有工艺损失和（）。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。