沧海桑田谁是谁的谁海誓山盟曾是谁的谁
[cāng hăi sāng tián shéi shì shéi de shéi hăi shì shān méng céng shì shéi de shéi]
A poetic statement that reflects profound changes over a long passage of time, implying everything including promises might transform or end eventually as time flows. It conveys both deep emotions and philosophical reflections.