1、check out

结账退房;结账离开(诊所);给…办理结账手续

They packed and checked out of the hotel.

他们收拾好东西，办理了退房手续。

I was disappointed to miss Bryan, who had just checked out.

我非常失望没有见着布赖恩，他刚退房走了。

了解清楚;核实;查实

Maybe we ought to go down to the library and check it out.

或许我们应该去趟图书馆，查个明白。

We ought to check him out on the computer.

我们理应在电脑上查清他的资料。

经证实是对的;符合要求

She was in San Diego the weekend Jensen got killed. It checked out.

詹森遇害的那个周末她在圣迭戈，后经查证情况属实。

Everything checks out.

查过了，一切正常。

2、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。