Final answer:
Jem loses his pants while escaping the Radleys' yard after a gunshot scare. He finds them mended and folded on the fence when he returns, suggesting Boo Radley's secret kindness.
Step-by-step explanation:
In chapters 4-7 of To Kill a Mockingbird, Jem loses his pants as he, Scout, and Dill flee from the Radleys' backyard after Mr. Radley fires a gunshot. Jem's pants get caught in the fence, and in a rush to escape without being seen, he leaves them behind. When Jem goes back for them later, he finds that his pants have been mended and neatly folded over the fence, as if someone knew he would come back for them. This mysterious act of kindness hints at the presence of Boo Radley, who is slowly starting to emerge as a character in the children's lives.