"There is no choice but the flowers fall away, and the swallows return as if they have known each other before." The line of work is clever and complete, fluent and implicit. This is also the reason why this poem is famous. But what is more interesting is the intention contained in this couplet. The withering of flowers, the passing of spring, and the passage of time are all irresistible natural laws. Although it is useless to linger on regrets, so I say "there is nothing I can do". This sentence is connected with "the sunset"; however, in this late spring atmosphere, I feel What is suffered is not just the helpless decline and disappearance, but also the gratifying reappearance. Isn’t the swallow returning gracefully like an old acquaintance who nested here last year? This sentence should be "when will you return". Although flowers falling and swallows returning are also in the foreground, once they are associated with "helplessness" and "déjà vu", their connotations become very broad, with the symbolic meaning of beautiful things. In the intertwining of regret and relief, there is a certain philosophy of life: all the beautiful things that are bound to disappear cannot be prevented from disappearing, but while they disappear, there are still beautiful things reappearing, and life will not become nothing because of their disappearance. . It's just that this kind of reappearance is not the same as the intact reappearance of beautiful things. It is just "deja vu".