2016年管理学原理真题:He starts to sing when I _____ the violin. A. play B. plays C. playing

He starts to sing when I _____ the violin. A. play B. plays C. playing A SONG TO SING 琴谱 Run about to sing的中文意思 tmorrow's song to sing 含有sit down here he can sing的英文歌 Id Like To Teach The World To Sing歌词 I am hearing her sing和I am listening to her sing. does he need to know? does he need to know? He ()has anthing to do