来自潘亚琼的问题
【Once____,thispowerstationwillsupplyalltheneighboringtownsandvillageswithelectricityA.itbeingcompletedB,itcompletedC.completedD.itcompleting为什么选C而不选B呢?】
Once____,thispowerstationwillsupplyalltheneighboringtownsandvillageswithelectricity
A.itbeingcompletedB,itcompletedC.completedD.itcompleting
为什么选C而不选B呢?

