adv.第一；首先
Firstly, state sovereignty is inseparable. 第一，国家主权不可分割。
Firstly,China should have a development program for young fencers. 第一，中国应有一项培养少年儿童击剑运动员的发展计划。
Firstly, let me tell you why he is a real father. 首先，让我告诉你他为什么是一个真正的父亲。
