单项选择题
As each MSI message will have a unique identity, the printing of messages already received correctly is（）.
A.automatically suppressed B.finished by the operator C.manually suppressed D.done again
单项选择题 SafetyNet is an international service for the broadcast and automatic reception of MSI by means of direct-printing through（）system.
单项选择题 Ship-to-ship distress alerting should be conducted by（）.
单项选择题 On-scene communications will normally take place between（）.
