单项选择题
A.it can break down under high heat and emit noxious fumes
B.it will decompose under prolonged storage and lose its effectiveness
C.fire has been known to flash back over the surface of an oil fire
D.it is ineffective in fighting fires in high-voltage electrical equipment
单项选择题 One advantage of the all-purpose nozzle is that it（）.
单项选择题 Once a vessel has loaded packaged hazardous cargo，the cargo spaces shall be inspected. The spaces shall also be inspected at least once in every 24 hours. The only exception to daily inspection is when（）.
单项选择题 On a ship，when may a work vest be substituted for a required life preserver?（）