two-unit system

• 双组系统

two-unit system的用法和样例：

例句

1. The report Friday quotes sources as saying gas had been fed into the second system this week and that the results of the proce already had been obtained.
   报导星期五援引消息人士的话说，工程人员这个星期已经向第二组系统中注入了气体，并已从相关程序中获得了结果。