单项选择题
Class C fires are best extinguished by （）.
A.foam extinguishers B.water spray equipment C.dry powder extinguishers D.soda-acid extinguishers
单项选择题 Class B fires are best extinguished by smothering, i-e（）.
单项选择题 Class A fires are best extinguished by quenching or cooling with （）.
单项选择题 A fire starts when the following （） factors come together.
