数控机床是采用数字控制技术对机床的加工过程进行自动控制的一类机床。

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。

夜间清理作业必须由电工安装照明灯具，保证有足够和安全的照明，方可进行夜间清理作业。

夜间清理作业必须由电工安装照明灯具，保证有足够和安全的照明，方可进行夜间清理作业。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

立式车床由于工件及工作台的重力由机床（）或推力轴承承担，大大减轻了立柱及主轴轴承的负载，因而能长期保证机床精度。

立式车床由于工件及工作台的重力由机床导轨或（）轴承承担，大大减轻了立柱及主轴轴承的负载，因而能长期保证机床精度。