这句中的caving和trail都啥意思?
问题描述：
这句中的caving和trail都啥意思?
91.Arid regions in the southwestern United States have become increasingly inviting playgrounds for the growing number of recreation seekers who own vehicles such as motorcycles or powered trail bikes and indulge in hill-climbing contests or in caving new trails in the desert.
91.美国西部的不毛之地正成为玩耍的地方,对越来越多拥有摩托车或越野单车类车辆的,喜欢放纵于爬坡比赛或开辟新的沙漠通道的寻欢作乐者具有不断增长的吸引力.
答
caving new trails应该是指开摩托或沙地车在沙漠中轧出深深的车辙那种景象.一般在沙地上只开过一次不会有很深的车辙（即达不到caving的程度）,只有连续不断的重复轧过,才会有深深的车辙.
如何用简洁的语言描述那种意境,我想不出来.可以去www.yeeyan.com看看,那里专门搞翻译的.