Complex sentence: The 1997--98 season was Sport Lisboa e Benfica's 94th season in existence and the club's 64th consecutive season in the top flight of Portuguese football, covering the period from 1 July 1997 to 30 June 1998.
Split into simpler sentences: The 1997--98 season was Sport Lisboa e Benfica's 94th season in existence and the club's 64th consecutive season in the top flight of Portuguese football. It covers the period from 1 July 1997 to 30 June 1998.