Complex sentence: Aretha was re-united with Curtis Mayfield after their earlier success together with the "Sparkle" soundtrack, but it has long been regarded as one of Aretha's poorest recordings, selling only about 100,000 copies.
Split into simpler sentences: Aretha was re-united with Curtis Mayfield after their earlier success together with the "Sparkle" soundtrack. However, this album has long been regarded as one of Aretha's poorest recordings, selling only about 100,000 copies.