（）, 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（）.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

不属于设备寿命的是（ ） A．物质寿命 B．经济寿命 C．技术寿命 D．市场寿命

设备寿命分为自然寿命、技术寿命和（）寿命。

关于设备的自然寿命、技术寿命和经济寿命，下列说法有误的是( )。

试述设备的物理寿命、技术寿命、经济寿命、折旧寿命的含义。

设备的寿命可分为 ( )①设备的物资寿命;②设备的技术寿命;③设备的经济寿命;④设备的折旧寿命;⑤设备的生产寿命

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。