单项选择题
A.64 cubic feet
B.35 cubic feet
C.100 gallons
D.500 liters
单项选择题 When using carbon dioxide to fight a fire on a bulkhead，the CO2 should be applied（）.
单项选择题 When using a high-velocity fog stream in a passageway，the possibility of a blow back must be guarded against. Blow back is most likely to occur when（）.
单项选择题 When used to fight fire，carbon dioxide（）.