鳍是鱼的运动器官，下列鱼鳍中，能够维持身体平衡的是（）。

完成“探究鱼鳍在游泳中的作用”这一实验后，小明惊奇地发现决定鱼运动的方向和产生前进动力的主要是（）

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。

面料经纬向判定，对于有布边的面料，与边平行的方向为（）（经向or纬向）

由国立山西大学1943年度新生入学试题清册中看到，考试内容包括：数学、史地、生物、公民和（）等科。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。