单项选择题
A.easy and expensive B.simple and certain C.dangerous and stable D.difficult and compulsory
In which year was the COSPAS-SARSAT system established?...
单项选择题In which year was the COSPAS-SARSAT system established?（）
A.1980 B.1981 C.1979 D.1982
When receiving a distress alert, the SAR authorities as...
单项选择题When receiving a distress alert, the SAR authorities ashore and the ships in the vicinity of the ship in distress will（）in a coordinated search and rescue operation with the minimum delay.
A.assist B.send a rescue vessel C.search the distress area D.reach the distress position at once
In areas covered by Inmarsat HF can be used as an（）to s...
单项选择题In areas covered by Inmarsat HF can be used as an（）to satellite communications.
A.alternation B.alternate C.alter D.alternative
