Complex sentence: Two 10-kilometre sized asteroids are now believed to have struck Australia between 360 and 300 million years ago at the Western Warburton and East Warburton Basins creating a 400-kilometre impact zone, according to evidence found in 2015 it is the largest ever recorded.
Split into simpler sentences: Two 10-kilometre sized asteroids are now believed to have struck Australia between 360 and 300 million years ago at the Western Warburton and East Warburton Basins creating a 400-kilometre impact zone. According to evidence found in 2015 it is the largest ever recorded.