（）, 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。

从法律上讲，要达成一项有效的合同，必不可少的环节是（）。

从法律上讲，要达成一项有效的合同，必不可少的环节是发盘和接受。

从法律上讲，要达成一项有效的合同，下列哪些环节不是必要环节是（）。

在国际贸易中，达成一项交易的两个必不可少的环节是发盘和接受。（　　）

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。