A.“六大禁令”和“保命條款” B.記號(hào) C.警示標(biāo)志 D.關(guān)于安全指示
A.需求閥打開(kāi),呼氣閥關(guān)閉 B.需求閥打開(kāi),呼氣閥打開(kāi) C.需求閥關(guān)閉,呼氣閥關(guān)閉 D.需求閥關(guān)閉,呼氣閥打開(kāi)
A.30ppmB.15mg/m3(10ppm)C.30mg/m3(20ppm)D.150mg/m3(100ppm)