1、probably

大概；或许；可能

The White House probably won't make this plan public until July.

白宫可能要等到7月份才会公开这个计划。

Van Gogh is probably the best-known painter in the world.

凡·高可能是世界上最知名的画家。

（用于缓和语气）大概，或许，可能

He probably thinks you're both crazy!

他可能认为你们两个人都疯了！

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。