小题1:B
小题1:D
小题1:A
小题1:根据It was a mountain bike he received for his 15th birthday that changed him.描述可知选B。
小题1:根据In 2001, after becoming a skillful skier, Saunders started his first long-distance expedition （探险）towards the North Pole.可知选D。
小题1:根据短文描述可知桑德斯在体育运动方面是一个成功人士。故选A。