Complex sentence: Kurt Donald Cobain (February 20,1967--c. April 5,1994) was an American musician and artist, best known as the lead singer, guitarist and primary songwriter of the grunge band Nirvana.
Split into simpler sentences: Kurt Donald Cobain (February 20,1967--c. April 5,1994) was an American musician and artist. He was best known as the lead singer, guitarist, and primary songwriter of the grunge band Nirvana.