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.
A.sometimes B.all times C.never D.partly
单项选择题 The information flow of the MSI broadcast must be controlled（）.
单项选择题 If EGC receiver shares a same antenna with INMARSAT MES, it means that it can receive MSI（）.
单项选择题 EGC safetyNet transmits（）types of messages for mariners.
