sentence: People compete bike-cross on a bumpy road. sentence:  A person sprays water on the bumpy road where the bikers pass. sentence:  A group of bikers leave the start line to start the motocross competition, while other group start to run bike-cross. sentence:  A person wearing white top take pictures to the bikers. sentence:  New groups of bikers start to run on the bumpy road to compete bike-cross.