Complex sentence: Shortly after Mulder gives Scully her birthday gift, an Apollo 11 commemorative key ring, a woman named Sharon Graffia comes by claiming to be Max's sister and telling them that Max was in a plane crash two hours earlier.
Split into simpler sentences: Shortly after Mulder gives Scully her birthday gift, an Apollo 11 commemorative key ring, a woman comes by, named Sharon Graffia. Sharon tells the agents that she is Max's sister and that he was in a plane crash two hours earlier.