9.A: Who ______the floor? It looks clean.B: It ______by my sister ten minutes ago.(A) mopped ; is mo
問題詳情
9.A: Who ______the floor? It looks clean.B: It ______by my sister ten minutes ago. (A) mopped ; is mopped (B) mopped ; was mopped (C) mops ; was mop (D) is mopping ; was mopped