单项选择题
An advantage of an ABC dry chemical over a carbon dioxide extinguisher is（）.
A.lack of toxicity B.the multipurpose extinguishing ability C.bum-back protection D.cooling ability
单项选择题 An advantage of nylon rope over manila is that nylon rope（）.
单项选择题 An aneroid barometer is an instrument（）.
单项选择题 An emergence sea anchor may be constructed by type of extinguisher?（）.
