Complex sentence: In 1915, Mayor John Mitchell appointed her to the New York City Board of Education, but she resigned all posts in 1915 in order to participate completely in the final drive to achieve the vote for women.
Split into simpler sentences: In 1915, Mayor John Mitchell appointed her to the New York City Board of Education. However, she resigned all these posts in 1915, in order to participate completely in the final drive to achieve the vote for women.