单项选择题
A.if he can do so without any risk to his vessel
B.if he can do so without undue delay
C.if he can do so without serious danger to his vessel or to individuals on board
D.without regard to any danger to his vessel
单项选择题 Each hose in the fuel transfer system for helicopter refueling must have a（）.
单项选择题 During storm conditions on a vessel，the mooring tensions should be adjusted so that（）.
单项选择题 During severe storms when survival becomes a major concern，it may become necessary to relieve high anchor tensions on the windward side of the unit by（）.