The fallen leaves know that the autumn wind is getting colder and the years are fleeting. "It means: when you see the fallen leaves on the ground, you know that autumn is coming, the weather is getting colder and colder, time flies, and you often think of the past." Both of these poems express that time flies, and the happy moment passes in a blink of an eye, inspiring people to cherish the present time more.
Related idioms:
1, a fallen leaf knows autumn.
Commentary: When I saw yellow leaves falling to the ground, I knew autumn was coming. Refers to the development and change of events can be predicted by signs.
Source: Songshi Puji's "Five Lantern Festival Yuan" Volume 20: "Leaves fall to know autumn, give Ming San." "Continued Lantern Biography": "The strings move differently, and the leaves fall to know the autumn." Han-Liu An's "Huai Nan Zi Shuo Shan": "When you see a leaf falling, you know the end of the year." Tang Mingzu's "Conan Xia Ji": "I hate the end of the world and shake down three glasses of wine, like falling leaves and knowing autumn."
2. Time flies (the sun and the moon fly like a shuttle)
Explanation: the sun and the moon fly like a shuttle, describing how time flies.
Source: Song Gordon's "A Story of Things and Huang Shu's Double Words": "The sun and the moon are like a shuttle, and the text is like the sea. Can't discuss, Huang Zhu dares to be lazy. "