（）, 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 （）.

根据不同层次的用户，信息系统有哪些类型？各类型信息系统的主要作用是什么？

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

我国第一部系统研究农学的著作是《（）》。

试题(59)评价信息系统经济效益的方法不包括 (59) 。(59)

简述农学（广义、中义、狭义）的含义。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。