Complex sentence: Grace Adelaide Jones (born 7 December 1899) is an English supercentenarian, at the age of, she is the oldest person in the United Kingdom and the last British citizen born before 1900 and the youngest living person born before 1900.
Split into simpler sentences: Grace Adelaide Jones (born 7 December 1899) is an English supercentenarian. At the age of, she is the oldest person in the United Kingdom and the last British citizen born before 1900.