Complex sentence: Robert Ritchie was a Hong Kong racecar driver who won the Macau Grand Prix in 1955, at the time of his win, he was a Sargent at the Royal Air Force.
Split into simpler sentences: Robert Ritchie was a Hong Kong racecar driver who won the Macau Grand Prix in 1955. At the time of his win, he was a sergeant in the Royal Air Force.