On the surface, the third sentence only describes the scene of the author and Li Bai. "Weibei" refers to the Chang 'an area where Du Fu is located; "Jiangdong" refers to Jiangsu and Zhejiang where Li Bai roams. "Spring Tree" and "Sunset" are just plain descriptions without any modification. Looking at it separately, the two sentences are very general, and there is nothing strange. However, the author organizes them in a joint, but naturally there is a wonderful close connection. That is to say, when the author misses Li Bai in Jiangdong in Weibei, it is also the time when Li Bai misses the author in Weibei in Jiangdong; The author looked at the southern sky, but only saw the clouds on the horizon. Li Bai looked at the northland from afar and only saw the colors of trees in the distance. Naturally, he saw their parting hatred, like "Spring Tree" and "Twilight Cloud", with a deep feeling of parting. The two poems imply the same infinite feelings of both sides. How rich the memories of all the good times together, the situation after their separation and the various situations at this time should be. These two sentences seem dull, but in fact they are tempered every word; The language is simple, but rich in meaning, and it is a famous sentence that has been sung all the time.
3. Expressed Du Fu's admiration for Li Baiqi and his poems; The author uses the method of scenery and emotion to write the feelings of missing deeply and emotionally.