Complex sentence: In January 1952, Turing started a relationship with a 19-year-old unemployed man, Arnold Murray, whom he had met outside the Regal Cinema when walking down Manchester's Oxford Road just before Christmas and had invited to lunch.
Split into simpler sentences: In January 1952, Turing started a relationship with Arnold Murray, a 19-year-old unemployed man. Turing met Murray just before Christmas outside the Regal Cinema when walking down Manchester's Oxford Road and had invited him to lunch.