Complex sentence: Between 1994-1995, the flight control center was refurbished, in 1996-1997 the runway surface was renovated and in 1998, the airport apron and taxiways were renovated.
Split into simpler sentences: Between 1994-1995, the flight control center was refurbished. In 1996-1997 the runway surface, and in 1998, the airport apron and taxiways were renovated.