"Back" appeared four times in the article, each time the situation was different, but the thoughts and feelings came down in one continuous line.
The first time is the beginning of the article, the title is "Hui", and there is a strong emotional atmosphere hanging over the whole article.
The second time was at the farewell scene of the station. The author gives a detailed description of his father's "back", which is the focus of his writing. Father's fat body, wearing a black cloth jacket and a dark blue cotton robe, trudged across the railway to buy oranges for his son. This shot shows the father's deep affection for his son, which moved his son to tears.
The third time, after the father and son said goodbye, the son watched his father's "back" disappear in the crowd, leaving his feelings and making people cry.
The fourth time was at the end of the article. When my son read his father's letter, his father's "back" reappeared with tears. He couldn't miss himself and echoed the beginning of the article.
This work shows the sincere feelings between father and son incisively and vividly, but it is different from the description of portraits in general works, focusing on the description of expressions, voices and smiles, but grasping the "back" of a character's image and making a detailed description at the expense of work.