Complex sentence: Producer Paul Samwell-Smith told him he could never put something like that on an album, and that it needed to be at least three minutes in length, although an acoustic demo exists of Stevens playing an early version which lasts almost three minutes.
Split into simpler sentences: Producer Paul Samwell-Smith told him he could never put something like that on an album, and that it needed to be at least three minutes in length. Although an acoustic demo exists of Stevens playing an early version which lasts almost three minutes.