单项选择题
Which device provides the main means in the GMDSS for locating ships in distress or their survival craft（）.
A.Radio direction finder B.Satellite EPIRBs C.MF/HF DSC D.VHF homing device
单项选择题 Which action should be taken on receipt of a GMDSS distress alert（）.
单项选择题 Where should the GMDSS radio log be kept on board ship（）.
单项选择题 When the GMDSS Radio Operator on watch hears“SECURITE”spoken three times he can expect to receive a message concerning（）.
