单项选择题
By using（）system a ship can send a distress message and know with certainty it will be received.
A.COSPAS-SARSAT B.SATELLITE C.terrestrial radio D.INMARSAT
单项选择题 For COSPAS-SARSAT system,（）usually transmit initial COSPAS-SARSAT alert.
单项选择题 COSPAS-SARSAT is intended to be used for（）.
单项选择题 Can MF/HF radiotelephone receive the MSI sent from the coast stations alone?（）
