单项选择题
A.100mg/m3 B.100ppm C.150ppm D.30mg/m3
A.0.0065m-1 B.0.009m-1 C.0.0075m-1 D.0.0095m-1
A.1倍 B.0.5倍 C.2倍 D.1.5倍
A.洞门 B.排水设施 C.照明 D.仰坡
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