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 because it hints that Doodle is no longer present in the narrator's life. The mention of the grindstone turning and the narrator remembering Doodle suggests a sad and nostalgic tone, which foreshadows that something significant or tragic has happened in relation to Doodle.
Learn more about foreshadowing in literature