选项A 后面已经说到JP连续当了18年的planning board的主席，前面不需要再提示前任

选项B (the former chair of the planning board and a board member),Joan Philkill attended more than 400 meetings and reviewed more than 700 rezoning applications. 前面的括号中成分变成主语，一个句子对个主语，错误;

同理排除C

选项D 两个完整句子没有连接词错误

选项E 正确 As （the chair of the planning board） for 18 consecutive years and （a board member） for 28 years，Joan Philkill attended more than 400 meetings and reviewed more than 700 rezoning applications.