Complex sentence: Matt Smith was announced on 1 June 2013 as stepping down from the role of The Doctor at the end of 2013, the casting of the Twelfth Doctor has yet to be announced.
Split into simpler sentences: Matt Smith was announced on June 1,2013 as stepping down from the role of The Doctor at the end of 2013. The casting of the Twelfth Doctor has yet to be announced.