单项选择题
A.blows the fire back toward the vessel
B.comes over the bow
C.comes over the stern
D.comes over either beam
单项选择题 A definite advantage of using water as a fire extinguishing agent is its characteristic of（）.
单项选择题 A cutoff valve in the fire-main system of a ship may be closed to protect the portion of the system on an exposed deck from（）.
单项选择题 A combustible gas indicator meter is calibrated to read the percentage of（）.