问题
单项选择题
When should a fire be ventilated?（）
A.When attacking the fire directly
B.When using a steam smothering system
C.When using the fixed CO2 system
D.All of the above
答案
参考答案：A
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When should a fire be ventilated?（）
A.When attacking the fire directly
B.When using a steam smothering system
C.When using the fixed CO2 system
D.All of the above
参考答案：A