A.立即 B.听监督指挥 C.根据当时实际情况决定是否 D.留下继续工作
A.1.8ppm;预警 B.2.8ppm;预告 C.3.6ppm;警惕 D.4.6ppm;警示
A.5ppm B.10ppm C.20ppm D.100ppm