1, which means different: the left flag and the right drum refer to two different places in geography. Zuoqi refers to Qishan in the west and Gushan in the east. Names are related to specific geographical location, landforms, history and culture.
2. Usage difference: the left flag and the right drum are coordinate phrases, which are used to describe the two places of the left flag and the right drum, emphasizing the contrast or correlation between them. Right flag is a separate word, which refers to another geographical location or other meanings.