Through comparison, the poor life and difficult situation of charcoal sellers are profoundly written, and the exploitation and oppression of the people by the rulers are exposed. .
Sell charcoal Weng to earn money and buy clothes and food. The old man wears simple clothes, and then uses the "one foot of snow" at night and the "ice trace" on the road as a foil, which makes people feel that the old man is pitiful. All this just reflects the fierceness of the fire of hope for the elderly: it is freezing in the cold, charcoal is expensive, and you can change more clothes and food.
Next, "the cow is hungry" and "two riding" reflect the disparity between workers and rulers; "A cart full of charcoal, a thousand Jin" and "Half a horse's red yarn, a foot's silk" contrast the cruelty of plunder in the "palace market". As far as the whole poem is concerned, the burning of the fire of hope in front is precisely to set off the sadness and pain of hope behind.