单项选择题
Seven short blasts continued for one minute means （）.
A. fire alarm B. boat alarm C. man overboard D. emergency alarm
单项选择题 Several sand boxes need （）.
单项选择题 When a ship is abandoned, all of the crew members hearing the alarm sounding should put on （）.
单项选择题 （）the moving parts on the davit of the lifeboat.
