First listen and then answer the question.
What mistake was made?
The great racing driver, Sir Malcolm Campbell, was the first man to drive at over 300 miles per hour. He set up a new world record in September 1935 at Bonneville Salt Flats, Utah. Bluebird, the car he was driving, had been specially built for him. It was over 30 feet in length and had a 2,500-horsepower engine. Although Campbell reached a speed of over 304 miles per hour, he had great difficulty in controlling the car because a tyre burst during the first run. After his attempt, Campbell was disappointed to learn that his average speed had been 299 miles per hour. However, a few days later, he was told that a mistake had been made. His average speed had been 301 miles per hour. Since that time, racing drivers have reached speeds over 600 mites an hour. Following in his father's footsteps many years later, Sir Malcolm's son, Donald, also set up a world record. Like his father, he was driving a car called Bluebird.New words and expressions 生词和短语
burst（1．7）/bə:st/ (burst, burst) v．爆裂
Notes on the text 课文注释
1 drive at over 300 miles per hour, 以每小时 300多英里的速度驾车。
2 30 feet in length, 30英尺长。
3 the first run, 开始的行程。
4 Following in his father's footsteps, 踏着父亲的足迹。