em = excecutive member 可以理解为正式会员每个nc (neighbourhood committee)和rc (resident committee)对应的都是30个名额。需要先做observer再promote成em，时间可能3-12个月 grc和smc都是新加坡的选区，grc=集选区 smc=单选区，每次大选都有机会重新划分，当前的各选区请看https://www.parliament.gov.sg/constituency-boundaries-map