Complex sentence: It passed about 28 lunar distances (LD) from the earth on December 25,2015, and will pass about 7 LD (0.0189 AU) on December 22,2018.
Split into simpler sentences: It passed about 28 lunar distances (LD) from the earth on December 25,2015. It will pass about 7 LD (0.0189 AU) on December 22,2018.