What is the last sentence of "beauty is old"?

Youth is fleeting and beauty is old.

Translation:

Good times are the easiest to pass, and beautiful faces are the easiest to grow old. It means that time flies and youth can't last long. It means to persuade people to cherish time and grasp youth.

These two sentences have no obvious source. These two sentences have no implicit meaning of ancient poetry, and their meanings are easy to understand. It should be derived from modern people's own feelings.

Probably similar are:

After Dongdi left, it was the prime of life. -Dai Shulun's The Feeling of Late Spring

Feng Tang is easy to get old, but Li Guang is hard to seal. -Wang Bo's Preface to Wang Teng Pavilion

I am going to die and be buried, but I don't know when Nong will die.

The man who buried the flowers is laughing today, but who did he know when he buried them?

Just watch the spring flowers gradually fall, it is the time when the beauty dies of old age;

No sad songs for me, I don't know what happened! -Cao Xueqin's "Burying Flowers"