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。

12世纪，蒙古族兴起于（）流域，谁统一蒙古各部，之后不断壮大，谁建立起全国统一政权元朝？

蒙古族的三大历史名著有（）、《蒙古黄金史》、《蒙古源流》。

蒙古族的三大历史著作是[蒙古秘史]、[蒙古源流]、[（）]。

历史上元朝共进攻日本几次？（）

元朝是中国历史上首个大一统的少数民族王朝。她疆域辽阔，民族众多。以下事件发生在元朝的是（）①建立了蒙古国②将西藏纳入行政版图③灭掉西夏政权④开凿了山东的会通河

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。