Pulmonary alveolus: Any of the 300 million or so small air spaces in the lungs where carbon dioxide leaves the blood and oxygen enters it.是什么意思_Pulmonary alveolus: Any of the 300 million or so small air spaces in the lungs where carbon dioxide leaves the blood and oxygen enters it.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句