问Tree planting day前面用什么介词

前面用介词on，例如：

1.Uh, well, on the, on the tree planting day and my, my family and I we went to the suburbs of Beijing and we planted serval trees there and I hope these young trees are still alive now.在植树节那天，我和我的家人到北京的郊区去，我们在那里种了一些树，我希望那些小树苗现在还活着.