求翻译：山地车越野赛是运动员在规定的山路赛道上进行集体出发,根据赛道的难度由裁判团来决定运动员所完成一定时间的骑行里程,最终以运动员到达终点的先后顺序决定排名的比赛。是什么意思？

Mountain bike cross-country athletes in the provisions of the mountain track to the collective departure, by a panel of judges to decide according to the difficulty of the track athletes completed some time riding mileage, and ultimately to the order of the athletes reach the finish line to determin

mountain biking racing athletes are provided in the mountain track circuit in a collective based on the degree of difficulty in the magistrates' decision to take time for the athletes completed the ride mileage athletes to reach the destination, and ultimately to the sequence of game rankings.

The mountainous region vehicle cross-country race is the athlete carries on the collective on the stipulation mountain road racecourse to embark, rolls according to the racecourse difficulty by the referee decided the athlete completes certain time to ride the good course, finally arrives the end po

Mountain bike Cross Hill Road, on the track of athletes in a specified group, and according to the difficulty of the track by a panel of judges to decide the players ride miles of completed by a certain time, ultimately decided to rank in the order of the players reach the end of the game.

I am honored to be a London 2012 volunteer, and is responsible for the preparation of the English on the Olympic events