Complex sentence: In Summer 2012 Students in Years 7-10 hosted an Inter-House Olympic Games to celebrate the 2012 Summer Olympics being hosted by London it started with a torch relay then an afternoon of Olympic themed events.
Split into simpler sentences: In Summer 2012 Students in Years 7-10 hosted an Inter-House Olympic Games to celebrate the 2012 Summer Olympics being hosted by London. It started with a torch relay, followed by an afternoon of Olympic themed events.