Complex sentence: Terri went to a local gym at 11:39 a.m. and worked out until about 12:40 p.m. By 1:21 p.m. she had arrived home and posted photos on Facebook of Kyron at the science fair earlier that morning.
Split into simpler sentences: Terri went to a local gym at 11:39am and worked out until about 12:40pm. By 1:21pm she had arrived home and posted photos on Facebook of Kyron at the science fair earlier that morning.