（）, 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 （）.

哈夫曼树是其树的带权路径长度（）的二叉树。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

结点的带权路径长度

树的带权路径长度（WPL）

简述结点的权、结点的带权路径长度、树的带权路径长度等基本术语的含义。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。