停车检修容器可燃气体含量不得大于()才能动火检修。
A.3%
B.1%
C.0.5%
D.0.2%
参考答案:D
区域联防的防守原则是什么?
Damage to cargo caused by dust is known as().
A.contamination
B.oxidation
C.tainting
D.vaporization