英语翻译肺泡是肺脏进行气体交换的基本单位,其表面被覆的单层肺泡上皮主要由肺泡翻译内容：Ⅰ型和Ⅱ型上皮细胞构成.肺泡Ⅱ型上

Alveolar is the basic unit of lung in air exchanging.The monolayer that covers the lung is constitute of type 1 and type Ⅱ alveolar epithelial cells.Type Ⅱ alveolar epithelial cells covers only 5%-10% surface of alveolar wall but make up 60% of the alveolar cells.It is also called graininess alveolar cells or secrection cells.The cells are multi-function cells in maintaining the structure and function of alveolar.