Complex sentence: John Gilbert Alexander (born 4 July 1951) is a former professional tennis player and was an Australian politician until his resignation on 11 November 2017 due to constitutional ineligibility arising from his dual citizenship of the United Kingdom.
Split into simpler sentences: John Gilbert Alexander (born 4 July 1951) is a former professional tennis player, and an Australian politician. On 11 November 2017, he resigned due to constitutional ineligibility arising from his dual citizenship of the United Kingdom.