Complex sentence: The New Barbarians were a rock band that played two concerts in Canada and eighteen shows across the United States in April and May 1979; in August 1979, the band also supported Led Zeppelin at the Knebworth Festival 1979.
Split into simpler sentences: The New Barbarians were a rock band that played two concerts in Canada and eighteen shows across the United States in April and May 1979. In August 1979, the band also supported Led Zeppelin at the Knebworth Festival 1979.