在正交调幅（QAM）编码技术中，载波信号的（）和相位被改变。

一种用载波信号相位移动来表示数字数据的调制方法称为

一种用载波信号相位移动来表示数字数据的调制方法称为( )键控法。

输出继电器（OR）通过一对（）触点将PLC的控制信号传递给负载。

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。

F1系列PLC—OR指令表示（）。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。