单项选择题
An advantage of a dry chemical over a carbon dioxide fire extinguisher is its（）.
A.greater range B.effectiveness on all types of fires C.cleanliness D.All of the above
单项选择题 An ABC dry chemical fire extinguisher would be LEAST effective against a fire in（）.
单项选择题 All portable fire extinguishers must be capable of being（）.
单项选择题 All of the following are part of the fire triangle EXCEPT（）.
