Complex sentence: He again worked at the ONTP from 1988 to 1989 as head of research, and he served in the government as Secretary of State for Agriculture from 1989 to 1990.
Split into simpler sentences: He again worked at the ONTP from 1988 to 1989 as head of research. Annadif served in the government as Secretary of State for Agriculture from 1989 to 1990.