可惜没如果只剩下如果
[kĕ xī méi rú guŏ zhĭ shèng xià rú guŏ]
Translating roughly as 'Unfortunately there's no such thing as ifs; there's only if,' this conveys regret over what could have been, emphasizing feelings of longing or missed opportunities where 'ifs' symbolize hypothetical scenarios not fulfilled.