gas recirculation

例句：

1. 1.The process of gas recirculation helps to improve the efficiency of the engine.
   气体再循环过程有助于提高发动机的效率。
2. 2.During the gas recirculation process, the exhaust gas is mixed with fresh air before being released into the atmosphere.
   在气体再循环过程中，废气与新鲜空气混合后才能排放到大气中。
3. 3. Gas recirculation systems are commonly used in industrial furnaces to reduce emissions and improve energy efficiency.
   工业炉中使用的气体再循环系统用于减少排放和提高能源效率。