challenge 
英 [ˈtʃæləndʒ]  美 [ˈtʃæləndʒ] 
n. 挑战；怀疑；艰巨的任务

v. 向……挑战；反对；需要；要求；刺激；激发

例句：
Mike had been challenged and he was not going to back away from the contest. 

迈克受到挑战，而面对这场比赛他是不会退缩的。

We challenged a team who called themselves `College Athletes'. 

我们向一支自称为“大学运动员”的球队发起挑战。

U.S. business today is challenged by aggressive overseas competitors. 

如今美国的商业受到海外竞争者咄咄逼人的挑战。

A mum slashed a neighbour's car tyre and challenged her to a fight after their daughters fell out. 

两家的女儿闹翻了之后，一位母亲划破了邻居的车胎，提出要和对方的母亲较量一番。