The solitary sail drifted away and disappeared at the end of the watery sky, leaving only the surging river flowing eastward.
The last two sentences of the poem look like landscape writing, but there is a poetic detail in landscape writing. Li Bai has been sending his friends to the boat, and the boat has already left, while he is still watching the sails in the distance by the river. Li Bai's eyes looked at the sail shadow until it gradually blurred and disappeared at the end of the blue sky, showing a long time to watch. The shadow of the sail has disappeared, but Li Bai still stared at it. Only then did he notice that at the junction of water and the sky, a river of spring water flowed far away, expressing his reluctance to friends and the depth of friendship.