0 (the situation of being faced with) something that needs great mental or physical effort in order to be done successfully and therefore tests a person's ability -- 挑戰；難題；考驗
1 an invitation to compete or take part, especially in a game or argument -- （尤指比賽或辯論）挑戰（書），邀請
3 an instruction given by a soldier or guard at a border or gate, telling someone to stand still and say their name and reasons for being there -- （哨兵或警衛）喝停盤查
4 the act of refusing to accept someone as a member of a jury -- （對某人出庭擔任陪審員表示的）反對，拒絕
5 to invite someone to compete or take part, especially in a game or argument -- （尤指比賽或辯論）挑戰，邀請
As with literature, a considerable theoretical challenge exists in relating the subjective to the intersubjective.
Section 2 begins with an overview of the theoretical challenge, and then presents a category-theoretic framework for deriving transition systems.
Countries are facing this challenge in many different ways, but one common factor is the increasing reliance on electronics and systems.
The challenge has come from what was supposed to be the heart of the mechanistic world view - from physics.
This paper addresses the technical challenges of implementing a producibility analysis tool.
Far from challenging gender roles or performing new ones, this was ' plasticity', or good old-fashioned drag.
However, on the other hand, certifying that a random k-tuple system has low discrepancy seems to be an algorithmic challenge.
Opposition parties lack an independent material base to effectively challenge the regime.
