If the beacon is mounted at a wrong place, it may（）by sea water, chemicals, exhaust and vibrations.

As each MSI message will have a unique identity, the printing of messages already received correctly is（）.

Monitoring is especially important in a highly automated system which is dependent on careful（）procedure and format.

The vessel has stayed in port for seven days because she needs（）.

Particular care should be（）in selecting CESs in areas where Ocean Regions overlap.