The first sentence, "Snow in the suburbs, dark clouds over the top", focuses on the heavy snow outside Huaqing Palace. The word "fly" has a dynamic aesthetic feeling, depicting the scenery of the north wind whistling and snowflakes flying in the suburbs of Gong Jin. The word "dark" shows the power of snow evacuation from the perspective of color, and evokes the sense of touch from the visual experience, which makes it easy for people to experience the biting chill outside the palace from the poetry picture, giving people a cold feeling.
In the second sentence, "Only when the palace falls, it will dry up", and the pen tip turns from outside the palace to inside. A word "only" defines the special scope of falling snow, and a word "convenient" vividly describes the scene of the rapid melting and disappearance of falling snow in the palace from the perspective of time, and implicitly writes the warmth in the palace, which is in contrast with the first sentence.
The third sentence "Green trees and green curtains set each other off" vividly depicts the harmony of spring in the palace. The underground hot springs of Huaqing Palace spew, and the palaces on the ground are resplendent and magnificent, and the forbidden walls are towering, which can keep out the wind and cold, so the temperature in the palace is high and the trees are green all year round. The "green trees" here represent the difference between the natural creators in the palace and those outside the palace, while the "blue curtain" reflects the luxury of the owner's life in the palace.
The phrase "no one knows it's cold outside" depicts the fatuous image of the owner of Huaqing Palace, who cares about feelings, state affairs and the sufferings of the people. The poet implicitly pointed out: since Xuanzong of Tang Dynasty didn't even know the change of natural phenology and the arrival of winter, how could he know "cold"? The king of a country doesn't know the taste of cold, how can he observe the state affairs clearly and remember the sufferings and joys of the people? Such a fatuous person provided the soil for the ambition of An Shi Rebellion to germinate and grow consciously or unconsciously.
This poem is novel in artistic conception and implicit in irony, which is in sharp contrast with the temperature difference inside and outside the palace, resulting in the scattered structure of the poem and ups and downs.