Complex sentence: The 1991 PBA Third Conference Finals is the best-of-5 basketball championship series of the 1991 PBA Third Conference, and the conclusion of the conference's playoffs, the Alaska Milkmen and Ginebra San Miguel played for the 50th championship contested by the league.
Split into simpler sentences: The 1991 PBA Third Conference Finals was the best-of-5 basketball championship series of the 1991 PBA Third Conference, and the conclusion of the conference's playoffs. The Alaska Milkmen and Ginebra San Miguel played for the 50th championship contested by the league.