What does it mean that "the green tiles are long in remembrance of the old rain, and the bamboo umbrella is deep in the alley for no reason" (with details)

Qingwa still remembers the rainy day when she met her lover before, but at this moment, the bamboo umbrella is still in the rainy lane in the south of the Yangtze River, and her lover is gone. Cleverly expressed the melancholy of recalling the past, things are different.

When I went back to the place where I had been, I saw the blue tiles precipitated by time and felt that time passed in a hurry. I have a sense of loss, as if I have returned to the past in a hazy way, but I really feel that things in front of me have changed.

Extended data:

This is a couplet, not a poem. The first part: the blue tile is long to remember the old rain, and there is no reason for Zhu Zhinian to go deep into the alley. Bottom line: the white stone is old in spring, and the five waters are old friends. It is generally believed that couplets are the most unique literary form in China. What is unique about it? Mainly in structure and language.

Couplets can be called "dual structure" style. Standard couplets always consist of two opposing parts. The former part is called "Lian", which is also called "sentence", "antithesis" and "antithesis". The latter part is called "bottom link", which is also called "antithesis", "antithesis" and "antithesis".

These two parts are paired. Only the upper part or the lower part can be regarded as semi-joint. Of course, many couplets, especially those written and hung, have horizontal comments in addition to the upper and lower couplets. Horizontal criticism is an organic part of this kind of couplets, which is often a summary, the finishing touch or compatible with couplets. Generally, it is four words, but also two, three, five and seven words.