Complex sentence: Jiang was among about a dozen military officers who were held responsible and punished in the aftermath of the accident, and was given demerit points which damaged his prospect for promotion, and his career was temporarily frozen.
Split into simpler sentences: Jiang was among about a dozen military officers who were held responsible and punished in the aftermath of the accident. He was given demerit points which damaged his prospect for promotion, and his career was temporarily frozen.