单项选择题
How should the letter O be pronounced when spoken on the radiotelephone?（）
A.OCK TOW BER B.O RI AN C.OSS CAH D.OA KAM
单项选择题 How（）the cargo at loading port?
单项选择题 Channel 13 (156.65 MHz)，the designated bridge-to-bridge channel，may NOT be used to（）.
单项选择题 All VHF marine band radios operate in the simplex mode，which means that（）.
