Complex sentence: As a member of David Cameron's first and second governments May was appointed as Home Secretary on 12 May 2010, shortly after Cameron became prime minister, and held the post until she succeeded Cameron as prime minister on 13 July 2016.
Split into simpler sentences: As a member of David Cameron's first government May was appointed as Home Secretary on 12 May 2010, shortly after Cameron became prime minister, and continued in the post as part of the second Cameron ministry. She held the post until she succeeded Cameron as prime minister on 13 July 2016.