challenge|challenged|challenges|challenging

如今孩子们挑战父母权威的程度远比过去高。

Children ___challenge their parents' authority far more nowadays than they did in the past.

他的女儿刚刚挑战了他，他正艰难地做决定。

His daughter had just ___challenged him and he was struggling for a decision.

她决定在会议上挑战新政策。

She decided to ___challenge the new policy at the meeting.

在我们的冒险中，我们面对了许多挑战。

We faced many ___challenges during our adventure.

我们喜欢像徒步旅行这样有挑战性的活动。

We enjoy ___challenging activities like hiking.

解决谜题可能非常有挑战性。

Solving puzzles can be very ___challenging.

这个项目相当有挑战性。

This project is quite ___challenging.

像骑士一样，我们骑马穿越全国，寻找冒险和富有挑战性的活动。

Like cavaliers we ride across the country looking for adventures and ___challenging activities.

解决这个问题非常具有挑战性。

Solving this problem was very ___challenging.

这对我们所有人来说都是一段充满挑战的时期。

This has been a ___challenging time for us all.