用on，是on Mid-Autumn Day。

用于时间的表达时，on可以用来表示具体的某一天（某些天）或具体某天的某一时刻。例句1.He is sitting beside her on the sofa.他挨着她坐在沙发上。

2. I admired the peeling paint on the ceiling.我“观赏”着天花板上正在剥落的油漆。

3. He got his winter jacket from the closet and dropped it on the sofa.他从衣橱里取出冬天穿的夹克，把它扔到沙发上。