单项选择题
It is（）for mariners to combine the SART with a float-free satellite EPIRB.
A.essential
B.compulsory
C.optional
D.inadvisable
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相关考题
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单项选择题
（）is a space system using one or more artificial earth satellites.
A.Satellite network
B.Satellite link
C.GMDSS
D.Satellite system -
单项选择题
For ships equipped with an SES, it is（）and（）for the operator to send a distress alert.
A.easy/reliable
B.difficult/cheap
C.stable/compulsory
D.easy/expensive -
单项选择题
In the COSPAS-SARSAT system distress signals are processed by（）and the resulting data are forwarded to（）through（）communication network.
A.MCC/LUT/RCC
B.LUT/MCC/RCC
C.LUT/RCC/MCC
D.LUT/RCC/LUT
