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、platform

（通常作为架放或着陆用的）平台

Some of these flood shelters are on raised platforms, which have allowed government helicopters to land amid the continuing floods.

其中一些防洪棚搭建在高台上，高台可供政府的直升机在持续的洪水中降落。

They found a spot on a rocky platform where they could pitch their tents.

他们在一块岩石平台上找到了一个可以搭帐篷的地方。

（政党的）纲领，政纲，宣言

a platform of political and economic reforms.

政治和经济改革纲领

The Socialist Party won a landslide victory on a nationalist platform.

社会党凭借民族主义政纲赢得了压倒性胜利。

（公开发表意见或表达愿望的）机会，论坛

The demonstration provided a platform for a broad cross section of speakers.

示威集会为具有广泛代表性的人士提供了发表意见的机会。