航海英语消防演习与作业单项选择题每日一练(2019.01.19)

单项选择题
Halon fire extinguishers are NOT effective when used on which types of fires?（）
A.Fires in electrical equipment
B.Flammable oils and greases
C.Class A fires in ordinary combustibles
D.Materials containing their own oxygen
单项选择题
How do you operate a portable CO2 fire extinguisher?（）.
A.Point the horn down
B.Turn cylinder upside-down
C.Break the rupture disc
D.Pull pin，squeeze grip
单项选择题
How does foam extinguish an oil fire?（）.
A.By cooling the oil below the ignition temperature
B.By removing the fuel source from the fire
C.By excluding the oxygen from the fire
D.By increasing the weight of the oil
单项选择题
Fire extinguishers on inspected vessels are numbered by size I through V，with I being（）.
A.used for electrical fires only
B.the smallest
C.the most accessible
D.the most effective
单项选择题
Foam extinguishes a fire mainly by（）.
A.cooling
B.chemical action
C.smothering
D.inerting the air