矿井空气中二氧化氮和一氧化碳的最高允许浓度为多少?
参考答案:
在矿井空气中二氧化氮的最高允许浓度为0.00025%,一氧化碳的最高允许浓度为0.0024%。
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C.融资家具照像机雍容华贵
D.北漂羸弱撒手锏饥肠漉漉
for his expert advice, John is often asked to help others with their personal affairs.
A.Having known
B.Being known
C.Known
D.Knowing