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。

哪一种挖土机不适合开挖停机面3m以下的土方？（）

（）适用于停机面以上土方开挖

适用于开挖停机面以下不深的土方，但不能用于水下开挖的是（）。

开挖停机面以上或停机面以下不深的地方的土石，最适用于选择（）

反铲挖土机适用于挖掘停机面以上的Ⅰ～Ⅲ类土。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。