单项选择题
An airplane should NOT send which signal in reply to a surface craft?（）
A.Opening and closing the throttle B.Rocking the wings C.Flashing the navigational lights off and on D.Flashing Morse T
单项选择题 An advantage of using chain lashing on heavy vehicles aboard Ro-Ro vessels is that it（）.
单项选择题 An advantage of the Christmas Tree towing method is to（）.
单项选择题 An “on-load” release system on a survival craft means the cable can be released（）.
