（）, 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 （）.

（）are liable to be stoten, pilfered or may damaged due to improper handing or stowage.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

电感三点式振荡器的振荡频率比电容三点式振荡器高。（）

三点式振荡器有（）和电感三点式电路。

三点式振荡器电路中振荡回路的三个电抗必须具备什么条件，才能使电路产生自激振荡？为什么？

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。