简述选择小学数学教学手段的依据，如何有效地运用小学数学教学手段的条件？

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.

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 （）.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

民粹主义则表现为“无原则地同情‘弱者’，不自觉地憎恨‘强者’”。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。