单项选择题
Equipment requirement vary according to（）.
A.Ship owner‟s will B.economic condition C.the area in which the ship operates D.different orders of all countries
单项选择题 The WWNWS establishes three types of navigational warning:（）.
单项选择题 Every ship must fitted with（）SART, and（）two-way VHF radio telephone.
单项选择题 In INMASAT-A service code 32（）.
