System often encountered (2) closed system 环境 No matter surroundings 无物质交换 exchange 封闭本系 closed system Energy transfer 能量交换 封闭体亲 4上一内容下一内容令回主目录 返回 2021/2/21上一内容 下一内容 回主目录 返回 2021/2/21 System often encountered （2）closed system No matter exchange Energy transfer