This sentence expresses a unique and beautiful artistic conception by depicting the scene of autumn river and morning fog. "Forgetting Sichuan" refers to the meaning of the cycle of life and death and the passage of time in China traditional culture. It is used here to describe autumn water, emphasizing that time is irreversible and life is short. Fog in the morning depicts the gradual disappearance of fog and the elegance and mystery brought by sunlight shining on the earth through the early morning mist. The whole sentence means that time flies like water, and it also shows the beauty of nature.