Complex sentence: They currently compete in Class A, the NSAA's classification for the state's largest schools, for all sports except Softball, Baseball, Tennis, and Soccer, in which they compete in Class B, Nebraska's second largest classification of schools.
Split into simpler sentences: They currently compete in mostly Class A, the NSAA's classification for the state's largest schools. The only sports in which they do not compete in Class A are Softball, Baseball, Tennis, and Soccer, in which they compete in Class B, Nebraska's second largest classification of schools.