按消息传送的方向与时间关系，通信方式分为：单工通信、半双工通信、（）。

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 （）.

双向身份认证是指移动用户与移动通信网络之间相互认证身份。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

假如某因素与某病关系的病例对照研究结果的OR值为0.3（P＜0.01），最可能的解释是（）。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。