A.have
B.had
C.are having
D.have had
您可能感興趣的試卷
你可能感興趣的試題
A.repairs
B.repairing
C.repaired
D.being repaired
A.which is assisted
B.that assist you
C.when you assisted
D.when being assisting
A.the range of antenna can cover everywhere in the world
B.we can know the ship’s exact position
C.that the distress alert can be located as soon as possible
D.antenna of permanent earth stations may be directed towards fixed points in the sky
A.which
B.on which
C.at which
D.in which
A.it necessary
B.it is necessary
C.it necessary to
D.necessary
最新試題
COSPAS-SARSAT is intended to be used for（）.
Particular care should be（）in selecting CESs in areas where Ocean Regions overlap.
As each MSI message will have a unique identity, the printing of messages already received correctly is（）.
SafetyNet is an international service for the broadcast and automatic reception of MSI by means of direct-printing through（）system.
By using（）system a ship can send a distress message and know with certainty it will be received.
（）will form the basis for distress alerting and safety calling.
In case a ship is in emergency or distress in any of 4 areas, it is required to use the continuous（）alert.
Distress traffic is the communication（）between the station in distress and the ships, aircraft, coast radio stations, coast earth stations and rescue centers participating in the rescue work.
Every lifeboat which is fitted with a fixed two-way（）radiotelephone apparatus with an antenna which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in its operating position.
Every lifeboat which is fitted with a fixed two-way vhf radiotelephone apparatus with（）which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in its operating position.