Complex sentence: Under President Corazon Aquino, he served as an Undersecretary in the Department of Labor and Employment (1989-1990), and was afterwards promoted to full Secretary, serving from 1990-1992.
Split into simpler sentences: Under President Corazon Aquino, he served as an Undersecretary in the Department of Labor and Employment from 1989-1990. Afterwards he was promoted to full Secretary, serving from 1990-1992.