Complex sentence: He participated in the last eligible race of his junior career at the 2006 World Junior Speed Skating Championships in Erfurt, taking first place in both the 500m, with a time of 35.83, and the 1500m, with a time of 1:49.71.
Split into simpler sentences: He participated in the last eligible race of his junior career at the 2006 World Junior Speed Skating Championships in Erfurt. There, he placed first in two events: the 500m with a time of 35.83, and the 1500m with a time of 1:49.71.