Complex sentence: On 18 December 2012, Marussia announced that Max Chilton will make his Formula One debut in 2013 after securing the second race seat at the team, making him the fourth different driver in the Marussia/Virgin team.
Split into simpler sentences: On 18 December 2012, Marussia announced that Max Chilton will make his Formula 1 debut next year after securing the second race seat at the team. This makes Chilton the fourth different driver in the Marussia/Virgin team.