1、trigger

(槍的)扳機

A man pointed a gun at them and pulled the trigger.

一名男子拿槍指著他們，接著扣動了扳機。

引爆;啟動;觸發

The thieves must have deliberately triggered the alarm and hidden inside the house.

盜賊肯定是故意觸發了報警器，然后躲在房子里。

The one thousand pound bomb was triggered by a wire.

那顆重達 1,000 磅的炸彈是由一根導線引爆的。

引起;發動;促使

the incident which triggered the outbreak of the First World War.

導致第一次世界大戰爆發的事件

The current recession was triggered by a slump in consumer spending

目前的經濟衰退是由消費支出驟跌引起的。

誘因;起因;引發…的原因

Stress may act as a trigger for these illnesses.

壓力可能會成為引發這些疾病的原因。

2、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。