Answer:
When Harry drew near the fire, he nearly singed his jacket.
Explanation:
The original sentence is compound, meaning it consists of two independent clauses, or clauses that can stand alone separately. On the other hand, a complex sentence consists of at least one dependent clause and one independent clause.
By rewriting Harry drew near the fire (which is an independent clause) as When Harry drew near the fire (which is a dependent clause that cannot stand alone), we create a complex sentence along with the independent clause that follows.