A challenging task or job requires great effort and determination.
Mike found a challenging job as a computer programmer.
迈克找到了一份富有挑战性的工作——当计算机程序员。
If you do something in a challenging way, you seem to be inviting people to argue with you or compete against you in some way.
Mona gave him a challenging look.
莫娜挑衅地看了他一眼。