"The Book of Songs·Xiaoya·Xiaomu".
"The Book of Songs·Xiaoya·Xiaomu" is a poem from the pre-Qin era, originally belonging to the fourth of the twelve chapters of the "Book of Songs". "Sang and Zi trees must be respected." Zhu Xi's Biography: "There are two trees, Mulberry and Zi trees. In ancient times, in a five-acre house, under the wall of trees, those who left their children and grandchildren to eat and use utensils... Planted by the parents of Mulberry and Zi trees. "Since the Eastern Han Dynasty, "Sangzi" has been used to refer to hometown or fellow villagers. Only Sang and Zi must be respectful and cautious. "It means that the mulberry tree in your hometown was planted by your parents, and you should show respect to it.