单项选择题
A.aimed at the source of the flames
B.fogged above the equipment
C.shot off a flat surface onto the flames
D.used to shield against electrical shock
单项选择题 When dry chemical extinguishers are used to put out class B fires，there is a danger of reflash because dry chemical（）.
单项选择题 A shipboard Oil Pollution Emergency Plan is required of（）.
单项选择题 Flooding of any compartment in a ship that results in a serious loss of reserve buoyancy will always（）.