Complex sentence: On March 12,2012, Swedish House Mafia released their next single titled "Greyhound" and their final and most famous track "Don't You Worry Child", also featuring John Martin was released on September 14,2012.
Split into simpler sentences: On March 12,2012, Swedish House Mafia released their next single titled "Greyhound". Their final and most commercially successful track "Don't You Worry Child", also featuring John Martin, was released on September 14,2012.