Is "adaptation" in ancient poetry plagiarism?

Of course, "adaptation" in ancient poetry is not plagiarism. In fact, many ancient poems and famous sentences are adapted from predecessors, such as:

Tang Wang Bo's Preface to Wang Tengting;

These include:

The sentence "Lonely sunset in Qi Fei, autumn waters * * * one color in the sky" is actually adapted from Zhou Yuxin's "Ma Su Fu" in the north:

"Fallen flowers and Chicago cover Qi Fei, and the green flag of willow is the same color".

Lin Bu s classical poem Xiao Mei in the Mountain Garden in the Northern Song Dynasty;

Flowers withered, unique plum blossoms swept out against the wind, and the scenery of the small park was beautiful.

"Mottled shadows hang obliquely on the clear shallow water, and their fragrance spreads peacefully in the moonlight dusk."

Cold birds want to fly, first glimpse plum blossoms; Butterflies will be enchanting if they know the beauty of plum blossoms.

Fortunately, there are micro-songs to compare, and there is no need for sandalwood gold statues.

Among them, "The shadows are shallow and the moonlight is fragrant" has been sung through the ages, but this poem actually comes from the residual sentence of Jiang Wei of the Southern Tang Dynasty who lived around 950 in the Five Dynasties:

"The bamboo shadow is horizontal, the water is shallow, and Gui Xiang floats at dusk".

If my answer is useful, please accept it. Thank you!