1、challenge

挑战;难题

I like a big challenge and they don't come much bigger than this.

我喜欢大的挑战，而所有挑战中再没有比这更大的了。

The new government's first challenge is the economy.

新政府面临的第一个难题是经济问题。

(成功地)应对挑战，迎接挑战

The new Germany must rise to the challenge of its enhanced responsibilities.

一个崭新的德国必须迎接挑战，承担更多的责任。

They rose to the challenge of entertaining 80 schoolchildren for an afternoon.

他们一个下午成功接待了80名学童。

怀疑，质疑(真实性、价值、权威等)

Democratic leaders have challenged the president to sign the bill.

民主党领袖对总统签署这项法案提出了质疑。

The move was immediately challenged by two of the republics.

此项动议立即遭到其中两个共和国的反对。

2、exhaust

使精疲力竭;使疲惫不堪

Don't exhaust him.

不要把他累坏了。

He took to walking long distances in an attempt to physically exhaust himself.

他开始长距离步行，试图耗尽自己的体力。

耗尽;用光

We have exhausted all our material resources.

我们已经耗尽了所有的物资。

They said that food supplies were almost exhausted.

他们说供应的食物几乎快要吃完了。