Complex sentence: Knowles first performed "If I Were a Boy" on November 6,2008, at the MTV Europe Music Awards, which was followed by another one on "The Oprah Winfrey Show" on November 13,2008.
Split into simpler sentences: Knowles first performed "If I Were a Boy" on November 6,2008, at the MTV Europe Music Awards. She then performed the song on "The Oprah Winfrey Show" on November 13,2008.