A.A flashing amber light
B.A fixed red light
C.A white flag raised and lowered vertically
D.A flashing white light
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A.at all times
B.in the bottom return mode
C.in the volume reverberation mode
D.only when there is no current
A.heavy
B.easily damaged
C.affected by temperature
D.costly relative to the strength ratio
A.stopper
B.screen
C.filter
D.restrictor
A.rising warm air
B.proximity to a low pressure area
C.inward spiraling circulation
D.clear dry weather
A.Has there been
B.Have there been
C.Has there
D.Have there
最新試題
A large basin cut into the shore，closed off by a caisson，and used for dry docking of ships is known as a（）.
A fishing vessel casualty must be reported to the Coast Guard if it involves（）.
How could lashing gear used aboard Ro-Ro vessels be stowed when not in use? （）
A heavy，thick-walled tube，usually steel，used between the drill pipe and the bit in the drill stem to weight the bit in order to improve its performance is called a（）.
A heavy steel curved arch constructed athwartships and above the after deck on a towing vessel is sometimes called a（）.
A large metallic device，mounted directly in the piping (usually located at the dock near the point where the vapor hose is attached)，designed to prevent the passage of a rapidly moving flame through the piping is called a（）.
A jack-up drilling rig being towed must（）.
A frame with two，or sometimes four，arms through which are threaded the guidelines and which is used to keep the drill stem and bit in line with the center opening in the temporary guide base is the（）.
A head-on situation at night is one in which you see dead ahead a vessel showing（）.
An inert gas system installed on a tanker is designed to（）.