Ancient poems describing lovelorn love

I want to know why my Jinse has fifty strings, and each string has a youthful interval. Zhuangzi daydreaming, a saint, was bewitched by butterflies, and cuckoo crowed in the imperial spring. Mermaids shed pearl-like tears on the moon-green sea, and the blue fields breathed their jade to the sun. A moment that should last forever has come and gone before I know it.

This poem is Jinse, a seven-character poem written by Li Shangyin, a poet in the Tang Dynasty, and one of the representative works of the poet. This poem is one of Li Shangyin's most difficult works. In the poem, the author recalls his boyhood, grieves and resents his unfortunate experiences, entrusts his feelings of sadness and resentment, borrows a lot of allusions, uses association and imagination to create a hazy realm, and conveys his sincere and strong thoughts. The whole poem is colorful, subtle and profound, sincere and touching.