In modern fathometers the sonic or ultrasonic sound waves are produced electrically by means of a(n)（）.

烟酸缺乏尿负荷实验测定尿N′-甲基烟酰胺排出量＜（）为缺乏。

A declaration made by the Master before a PRC Consul，giving particulars regarding heavy weather or other incidents which may have caused damage to the vessel or cargo，through no fault of the vessel，her officers，or crew is a(n)（）.

A vessel or object being towed astern shall display a(n)（）.

The movement of water away from the shore or downstream is called a(n)（）.

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.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

A series of brief showers accompanied by strong，shifting winds may occur along or some distance ahead of a(n)（）.

A current moving across a lock entrance toward the river or toward the dam is called a(n)（）.

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。