Complex sentence: Jack Gamble is a professional rugby league footballer who played in the 1960s, playing at representative level for Yorkshire, and at club level for Castleford, as a, i.e. number 3 or 4.
Split into simpler sentences: Jack Gamble is a former professional rugby league footballer who played in the 1960s. He played at representative level for Yorkshire, and at club level for Castleford, as a, i.e. number 3 or 4.