Complex sentence: Mark Nielsen (born August 25,1964) was a Connecticut state senator during the 1990s and later served as legal counsel and chief of staff to former Massachusetts Governor Mitt Romney.
Split into simpler sentences: Mark Nielsen (born August 25,1964) is an attorney who has worked in the public and private sectors. He was a Connecticut state senator during the 1990s and later served as legal counsel and chief of staff to former Massachusetts Governor Mitt Romney.