Complex sentence: Pakistan's first semi-professional football league began on May 28 1948 as the National Football Championship (NFC); the league was a knock-out competition, which remained as the top football league in the country until 2004 with the introduction of the Pakistan Premier League.
Split into simpler sentences: Pakistan's first semi-professional football league began on May 28 1948 as the National Football Championship. The league was a knock-out competition, which remained as the top football league in the country until 2004 with the introduction of the Pakistan Premier League.