Complex sentence: After quitting the band in 1983 Duncan went on to play in several other bands including Gin Goblins, The Blood Uncles and also played a couple of gigs for Nirvana as a second guitarist.
Split into simpler sentences: After quitting the band in 1983 Duncan went on to play in several other bands including Gin Goblins and The Blood Uncles. He also played a couple of gigs for Nirvana as a second guitarist.