Complex sentence: Blanche Thebom (September 19,1915March 23,2010) was an American mezzo-soprano who sang with the Metropolitan Opera in New York City for almost twenty years.
Split into simpler sentences: Blanche Thebom (September 19,1915March 23,2010) was an American operatic mezzo-soprano. In her own country she had a long association with the Metropolitan Opera in New York City which lasted nearly twenty years.