单项选择题
A flame screen（）.
A.permit the passage of vapor but not of flame B.prevents the passage of flammable vapors C.prevents inert gas from leaving a tank D.permits vapors to exit but not enter a tank
单项选择题 A foam-type portable fire extinguisher is most useful in fighting a fire in（）.
单项选择题 A foam-type portable fire extinguisher would be most useful in combating a fire in（）.
单项选择题 A galley grease fire on the stove may be extinguished using（）.
