Complex sentence: Marden has participated in hundreds of group exhibitions, and has also been the subject of numerous one-person shows and retrospectives, beginning with his 1975 retrospective at the Solomon R. Guggenheim Museum in New York.
Split into simpler sentences: Marden has participated in hundreds of group exhibitions, and has also been the subject of numerous one-person shows and retrospectives. His first museum show was the 1975 retrospective at the Solomon R. Guggenheim Museum, in New York.