The monosyllabic word "open、break" both have developed the meaning "open" and the word "open" has also involved in phrases like“open up”and "open on". After the Modern Times, the use of "open" as the meaning of "open up" was mostly used in disyllable word, while monosyllabic only rarely used in spoken language. Meanwhile, "break", as for the meaning "open up", its "monarch" has gradually been replaced by disyllable phrase "open on". In Modern Chinese, disyllable phrase "open up" has become a commonly used phrase. In the end, the paper analyzes the reason for the evolution of the substitution.