Complex sentence: During the Second Plenary Session of the 9th Central Committee, from August-September 1970, Mao became uncomfortable with Lin's growing power, and began to maneuver against Lin by undermining his supporters and attacking some of Lin's suggestions at the conference.
Split into simpler sentences: During the Second Plenary Session of the 9th Central Committee, from August-September 1970, Mao became uncomfortable with Lin's growing power. Lin was opposed by and began to maneuver against Lin by undermining his supporters and attacking some of Lin's suggestions at the conference.