单项选择题
What channel is general communication used?（）
A.any appropriate channel except public communication B.any appropriate channel except for public communications C.any appropriate channel besides public communication D.any appropriate channel beside public communication
单项选择题 What’s the advantage when using the satellites?（）
单项选择题 Any ships fitted with SES can（）and（）through the satellite system when sending a distress alert.
单项选择题 It is quite（）for an SES operator to send a distress alert.
