单项选择题
Which radiotelephone signal indicates receipt of a distress message?（）
A.Roger wilco B.Romeo，romeo，romeo C.SOS acknowledged D.Mayday roger
单项选择题 Which is NOT a distress signal?（）
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?（）
