Final answer:
Sentence 4 foreshadows that Doodle is no longer present in the narrator's life.
Step-by-step explanation:
The sentence from the excerpt that is foreshadowing is Sentence 4. It foreshadows that Doodle is no longer present in the narrator's life. The mention of the grindstone turning and time with all its changes being ground away implies that the narrator is reminiscing about the past and remembering Doodle, suggesting that something tragic happened to Doodle in the story.
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