单项选择题
A.A continuous sounding with any fog signal apparatus
B.A signal sent by radiotelephone consisting of the spoken word Mayday
C.An International Code Signal of N.C
D.The firing of green star rockets or shells
单项选择题 When testing a Class A EPIRB you will know the EPIRB is working properly if you hear on 99.5 Mhz FM or any vacant frequency on a nearby AM radio（）.
单项选择题 What is the primary purpose of a splint applied in first aid?（）
单项选择题 What is the normal length of anchor cable used to anchor a vessel?（）