What does Fu Lei mean by quoting Li Bai's poems?

"Letters from Fu Lei" quoted Li Bai and Du Fu's poems to praise the majestic momentum of the Yellow River and the Yangtze River: "How can the water of the Yellow River move out of heaven and enter the ocean? It's gone forever! _ _ _ _ _ _ _ _ Leaves fall like the spray of a waterfall, _ _ _ _ _ _, while I watch the long river roll forward! "