Ten years to plant trees, a hundred years to educate people comes from Mencius. A country's ten-year plan is to plant trees, and its hundred-year plan is to cultivate talents. This is Mencius' political theory. The latter usage, with the latter half sentence, indicates the importance and difficulty of talent training.
The kindness of inserting willows comes from "inadvertently inserting willows into the shade", which is a metaphor for the teacher's cultivation.
Generally speaking, the whole sentence means that talent training is very important and difficult, so the teacher's career is lofty and great, and the teacher's kindness to me will never be forgotten.
It takes ten years to plant trees and a hundred years to cultivate people "is a famous saying of Guan Zhong in Guan Zi Quan Xiu". . The original text of this sentence is: "A year's plan is like a valley of trees; A ten-year plan is not like a tree, and a hundred-year plan is not like a tree. " Metaphor personality training is not a one-off event, it takes a long time to accumulate and precipitate!
Meaning: It represents gratitude for the teacher's training and can also be used to represent the kindness of the first teacher. It comes from the meaning of "inadvertently inserting willows into the shade" and "predecessors inserted willows into the shade" Here is a metaphor for the cultivation of teachers, without asking for anything in return. The sentence "I will never forget the kindness of planting a willow tree" means: how can I forget the kindness of my teacher to my cultivation?
"It takes ten years to plant trees and a hundred years to educate people": It is a metaphor that it takes a long time for young trees to become useful. From "Guanzi Quanxiu III": "A year's plan is nothing more than a tree valley; The ten-year plan is nothing more than a tree; Lifelong planning is nothing more than cultivating people. A tree gets a tree, and the valley is also; Ten wins in one tree, and wood is also; There are many things in a tree, and so are people. I plant it, like god uses it, and I walk like god, only the king's door.
Mr. Lu Xun, whose original name was Zhou Shuren, also took this meaning, bearing the high hopes and sustenance of the elders for the younger generation.