What is the role of the second couplet of Du Mu in Xijiang Huaigu Hall? Please briefly analyze what kind of thoughts and feelings poetry shows.

Borrowing allusions, Cao Fu wrote the magnificent scene of Xijiang River with their ridiculous words, and compared it with the leisurely breeze blowing the river, expressing that life is just a drop in the ocean and a moment in the vast universe. Even if it was once brilliant, it is just a handful of loess and a wisp of dust in the future.