单项选择题
A.All required documents and publications may have to be produced
B.Licensed GMDSS radio operators may be required to demonstrate equipment competencies
C.All required equipment must be fully operational
D.All of the above
单项选择题 Downwind for 1 miles，alter to starboard 90 degrees，go down this course for 1 mile；Then alter 90 degrees to starboard and go down this course for 2 miles；Then alter 90 degrees to starboard and go down this course for 2 miles；Keep adding 1 mile ever time you alter to starboard．This operation is（）search pattern
单项选择题 Course directed by the OSC or CSS to be steered at the beginning of a search is（）.
单项选择题 Changing rescuers while carrying out artificial respiration should be done（）.