1、challenge

挑戰(zhàn);難題

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

我喜歡大的挑戰(zhàn)，而所有挑戰(zhàn)中再沒有比這更大的了。

The new government's first challenge is the economy.

新政府面臨的第一個難題是經(jīng)濟問題。

(成功地)應對挑戰(zhàn)，迎接挑戰(zhàn)

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

一個嶄新的德國必須迎接挑戰(zhàn)，承擔更多的責任。

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

他們一個下午成功接待了80名學童。

懷疑，質疑(真實性、價值、權威等)

Democratic leaders have challenged the president to sign the bill.

民主黨領袖對總統(tǒng)簽署這項法案提出了質疑。

The move was immediately challenged by two of the republics...

此項動議立即遭到其中兩個共和國的反對。

2、call up

(給…)打電話

When I'm in Pittsburgh, I call him up.

我每到匹茲堡,都給他打電話。

He called up the museum.

他給博物館打了電話。

(陸、海、空軍)征召…入伍

Youngsters coming up to university were being called up.

快上大學的青年人受到征召。

The United States has called up some 150,000 military reservists.

美國已經(jīng)征召了約15萬名預備役軍人。

選中,挑選(…參加運動隊)

He is likely to be called up for Thursday's match against Italy.

他有可能被選中參加星期四對意大利的比賽。

3、step up

增加(數(shù)量等);提高(速度、強度等)

He urged donors to step up their efforts to send aid to Somalia.

他敦促各捐贈方加快速度將援助物資送往索馬里。

Security is being stepped up to deal with the increase in violence.

正在加強安保工作以應對日益增多的暴力活動。