Complex sentence: There were such events included in archery, athletics, equestrian, fencing, judo at the 2010 Summer Youth Olympics, modern pentathlon, table tennis, and triathlon, and a number of pairs in doubles tennis were formed by athletes from two different NOCs.
Split into simpler sentences: There were such events included in archery, athletics, equestrian, fencing, judo at the 2010 Summer Youth Olympics, modern pentathlon, table tennis, and triathlon. Furthermore, a number of pairs in doubles tennis were formed by athletes from two different NOCs.