单项选择题
A combustible gas indicator meter is calibrated to read the percentage of（）.
A.vapor to oxygen B.the flammable limit concentration C.the autoignition concentration D.the lower explosive limit concentration
单项选择题 A class C fire would be burning（）.
单项选择题 A class B fire is most successfully fought by（）.
单项选择题 A Certificate of Inspection issued to a small passenger vessel describes（）.
