单选题
Many years ago there was a huge oil refinery fire. Flames shot hundreds of feet into the air. The sky was thick with, black smoke. The heat was so intense that firefighters had to park their trucks a block away and wait for the heat to die down before they could begin to fight the fire. However, it was about to rage out of control. Then, all of a sudden, from several block away came a tire truck racing down the street. With its brakes screeching,, it hit the curb in front of the fire. The firefighters jumped out and began to battle the blare. All the firefighters who were parked a block away saw this, and they jumped into their trucks, drove down the block and began to fight the fire, too. As a result of that cooperative effort, they were just barely able to bring the fire under control. The people who saw this teamwork thought: "My goodness, the man who drove that lead fire track—what an act of bravery!" They decided to, give him a special award w recognize him for his bravery in leading the charge. At the ceremony the mayor said, "Captain, we want to honour you for a fantastic act of bravery. You prevented the loss of property, perhaps even the loss of life. If there is one special thing you could have -- what would it be?" Without hesitation, the captain replied, "Your Honour, a new set of brakes would be nice!/
单选题
The expression "die down" on Line 3, Paragraph 1 means______.