challengen.挑战；邀请比赛；盘问；质疑v.向 ... 挑战；盘问；质疑challenge and diffieuhies困境Challenge and opportunity挑战与机遇challenges and adventures挑战和冒险challenge for jurisdiction管辖权异议challenge to head the ball争着顶球Challenges of African Union非洲联盟面临的挑战Challenge and Opportunities挑战challenge the law personally[法] 以身试法challenges and opportunities挑战与机遇challenge/response scheme挑战/应答认证机制