1、challenge

挑戰;難題

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

我喜歡大的挑戰，而所有挑戰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濟問題。

(成功地)應對挑戰，迎接挑戰

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，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、concentrate

全神貫注;集中（心思）

It was up to him to concentrate on his studies and make something of himself.

是否能專心學習并取得一定成就要靠他自己。

Water companies should concentrate on reducing waste instead of building new reservoirs.

自來水公司應該集中精力減少水浪費，而不是修建新水庫。

使集中;使匯集

Italy's industrial districts are concentrated in its north-central and north-eastern regions.

意大利的工業區集中在該國中北部和東北部地區。

Most development has been concentrated in and around cities.

土地開發主要集中在城市及周邊地區。