Appreciate this poem: Who pitied a shadow and lost Chung Shan Man?

In order to accurately appreciate this famous sentence by Du Fu, a poet in the Tang Dynasty, we have to understand the lonely goose/flying goose: "The lonely goose flies without pecking. The geese disappear in the sea of clouds, who will pity the geese in the sky? Looking at the horizon, I seem to see the figure of my companion; The voice in the valley seems to hear the voice of the companion. The wild crow has no feelings and is noisy. " Shadow refers to the shadow of a lonely goose flying alone in the sky, tiny and pitiful, but without a companion worthy of pity. Wan Zhongyun means that the geese fly high and blend into the vast sea of clouds, making the lonely geese lose contact. This famous sentence describes loneliness and sadness, from geese to people, but also sadness. Lonely geese should land as soon as possible, drink water, eat, give up looking for the time being and learn the lifestyle of wild crows. In the process of pursuing big goals, isn't it difficult for people to get close to thousands of clouds?