单项选择题
If you are transmitting a distress message by radiotelephone you should（）.
A.use English language B.always use the International Code C.preface it by the word "Interco" D.follow the transmission with the radio alarm signal
单项选择题 How is “radio silence” imposed?（）
单项选择题 Distress signals may be（）.
单项选择题 Distress flares and smoke signals for small passenger vessels（）.
