Complex sentence: He was the President of the National Assembly from 1981 to 1998 and is currently the President of the Senate (since 1999), and has also served as Cambodia's acting Head of State many times before.
Split into simpler sentences: He was the President of the National Assembly from 1981 to 1998 and is currently the President of the Senate (since 1999). He has also served as Cambodia's acting Head of State many times before.