¹ / 5tFAlIndV; `tFAlIndV/ n
~ (to sb) (to do sth) invitation or call (to sb) to take part in a game, contest, fight etc to prove who is better, stronger, more able, etc 约请或要（某人）参加比赛﹑ 竞赛﹑ 战斗等以证明谁更好﹑ 更强﹑ 更能干等; 邀请比赛; 挑战: issue/accept a challenge 发出[接受]挑战.
order given by a sentry to stop and say who one is 哨兵发出的止步命令, 并问来者是谁: The sentry gave the challenge, `Who goes there?' 哨兵查问: 谁在那儿?
~ (to sth) statement or action which questions or disputes (sth) 对（某事物）表示怀疑或争论的言论或行为异议; 质问; 怀疑: a serious challenge to the Prime Minister's authority 对首相的权威性郑重提出的异议.
difficult, demanding or stimulating task 艰巨的﹑ 高难度的或有激励性的任务: She likes her job to be a challenge. 她喜欢艰巨的工作. * Reducing the gap between rich and poor is one of the main challenges facing the government. 缩小贫富之间的差距是政府面临的主要难题之一.
formal objection, eg to a member of a jury 正式的反对（如反对陪审团的一个成员）.