I think it would be;
After Harry drew near the fire, he nearly singed his jacket.
To change the compound sentence about Harry into a complex sentence, you can write, "After Harry drew near the fire, he nearly singed his jacket." This highlights the cause-and-effect relationship by using a subordinate clause. Alternatively, you could say, "He nearly singed his jacket after he drew near the fire," emphasizing the main action first.
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