Final answer:
The poem's structure is focused on showcasing the changes in the speaker's life and the swimmin' hole, emphasizing nostalgia and the loss of youth through the altered landscape.
Step-by-step explanation:
The poem is structured to show the change in the speaker and the swimming hole. Through the juxtaposition of the past and present, the speaker reflects on the transformation that both he and his beloved swimmin'-hole have undergone. This transformation is portrayed with a sense of loss and nostalgia as the physical changes in the landscape mirror the changes in the speaker's life.
The passage illustrates the passage of time and its impacts, invoking a sense of sorrow over the loss of youth and the inevitable changes that occur in one's life and environment. The swimmin' hole, once a place of joy and freedom, is replaced by the symbol of modern progress, the railroad bridge, reflecting the speaker’s loss of innocence and the passing of time.
Ultimately, the melancholy tone emphasizes the speaker’s yearning to return to simpler times, contrasting with the permanent alterations of both the physical space and his life. The poem laments the inability to reclaim the past, as the speaker is left to grieve for what was once a source of happiness and refuge.