Explanation: Foundation to explore things in depth. Understand that things in context. Ba Jin's "Autumn" Thirteen: "Shu-hua to the bottom and asked: 'Dad talk to you about what three things?'" Guo "Li Bai and Du Fu, Li Bai and Du Fu's poetry exchanges": "This poor final at the end to ask the question, it seems to be the true meaning of Li Bai's close. "