The minimum detectable concentrations are less than 0.1 ppm for H2, O2 and CH4, and 0.5 ppm for CO.是什么意思_The minimum detectable concentrations are less than 0.1 ppm for H2, O2 and CH4, and 0.5 ppm for CO.在线翻译_英语_读音_用法_例句