Complex sentence: Marina Sirtis (born) is a Greek-British-American actress who is most noted for playing the Human/Betazoid Commander Deanna Troi, ship's counselor, on the television and film series'.
Split into simpler sentences: Marina Sirtis (born) is a British-American actress of Greek descent. She played the role of the human/Betazoid Commander Deanna Troi, ship's counselor, on the television and film series'.