单项选择题
The COSPAS-SARSAT 406mhz system was adopted as an element of the GMDSS by IMO in（）.
A.1982 B.1980 C.1984 D.1988
单项选择题 which function is the most important one of the GMDSS.（）
单项选择题 The quality of EGC message is（）affected by the position of the ship, the time of reception and climatic condition.
单项选择题 The information flow of the MSI broadcast must be controlled（）.
