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單項(xiàng)選擇題

why should the SES operators be very careful when the ship enters the area where three ocean regions overlap? Because（）.

A.the weather over there is always terrible
B.the condition there is complicated
C.the signals are too strong
D.their SES may receive the signals from unwanted satellite

單項(xiàng)選擇題

The quality of EGC messages is（）affected by the position of the ship, the time of reception and climatic conditions.

A.sometimes
B.all times
C.never
D.partly