Task: Question Generation
Input (English):  "Tom Bailey" is born in the fictitious town of Rivermouth, New Hampshire, but moves to New Orleans with his family when he is 18 months old. In his boyhood, his father wants his to be educated in the North and sent him back to Rivermouth to live with his grandfather, Captain Nutter. Nutter lives with his sister and an Irish servant. There, Tom becomes a member of a boys' club called the Centipedes. Together, the boys become involved in a series of adventures. In one prank, the boys steal an old carriage and push it into a bonfire for the [Fourth of July. During the winter, several boys build a snow fort on Slatter's Hill, inciting rival boys into a battle of snowballs. Later, Tom and three other boys combine their money to buy a boat named Dolphin and sneak away to an island. Tom also befriends a man nicknamed Sailor Ben, whom Tom originally meets on the ship that took him away from New Orleans. Revealed as the long-lost husband of Captain Nutter's Irish servant, Ben settles in Rivermouth in a boat-like cabin. Sailor Ben helps the boys fire off a series of old cannon at the pier, much to the confusion of the local townspeople. When his father's banking job fails, Tom is invited by an uncle to work in a counting-house in New York.
Output (English): What do the boys do in winter?