Complex sentence: John "Jack" Moore was an English professional rugby league footballer who played in the 1930s, and 1940s, playing at representative level for England, and at club level for Bradford Northern, as a, i.e. number 13, during the era of contested scrums.
Split into simpler sentences: John "Jack" Moore was an English professional rugby league footballer who played in the 1930s, and 1940s. He played at representative level for England, and at club level for Bradford Northern, as a, i.e. number 13, during the era of contested scrums.