Xin Qiji, a poet in Song Dynasty, used the word "one" extensively in Yuan Yu Xia, expressing the poet's yearning for his old friend on the night of Yuan Dynasty. In that sentence, "I expect, I think, I am green, I am in my heart." In Chinese, "Yi" means mood, which makes the whole poem more intense. This application enhances the lyrical effect and makes readers better feel the poet's inner entanglement and yearning.
With the evolution of Chinese, "one" gradually withdrew from the common vocabulary of modern Chinese and no longer appeared in various sentences like ancient Chinese. However, in some literary works, ancient poems and traditional culture, Yi still occupies an important position. Mastering the context and meaning of "Yi" is of self-evident significance for understanding ancient Chinese and appreciating China traditional culture. In today's Chinese, "one" is mainly used in oral communication, which can express confirmation, approval and inquiry, such as "yes" and "going out".