Mention is a common rhetorical method in ancient Chinese  In order to make the sentence compact and concise, combine the content that should have been expressed in two phrases or sentences into one phrase or sentence
When merging, the same elements are put together so that there is a separate relationship between the front and back parts of a phrase or sentence
Song of everlasting regret: the moonlight is always sad and resentful when I see the moonlight in the palace, and I hear the sad music of the rain bell in the rain at night.