A-A+ Mary saw her son_________the piano when she ca 2022-08-06 10:18:45 问答库 阅读 178 次 问题详情 Mary saw her son_________the piano when she came to the room.A.playingB.playC.playedD.to Cay请帮忙给出正确答案和分析,谢谢! 参考答案 正确答案:A