Simplify the following text for a Grade 7 native English-speaking person.
Original: John Campbell Ross ( 11 March 1899 â `` 3 June 2009 ) was at the time of his death Australia 's oldest man and the last Australian veteran of the First World War .
Simplified: John Campbell Ross ( 11 March 1899 - 3 June 2009 ) was the last living Australian World War I veteran .