Extremely flammable gas. Hydrogen is very light and may collect in the upper portions of storage areas. Hydrogen burns with an almost invisible flame.是什么意思_Extremely flammable gas. Hydrogen is very light and may collect in the upper portions of storage areas. Hydrogen burns with an almost invisible flame.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句