1、vital

a、必要的;至關重要的;必不可少的

The port is vital to supply relief to millions of drought victims.

這個港口對向數百萬旱災災民提供救援物資是至關重要的。

Nick Wileman is a school caretaker so it is vital that he gets on well with young people.

尼克·威爾曼是學校的管理員，因此與年輕人搞好關系很重要。

b、充滿活力的;生氣勃勃的

They are both very vital people and a good match.

他倆都很有活力，十分般配。

They have something important to say and vital and radical ways of saying it.

他們有些重要的事情要說，言辭會比較激烈。

2、critical

a、極重要的;關鍵的

The incident happened at a critical point in the campaign.

該事件發生在競選活動的關鍵時期。

Environmentalists say a critical factor in the city's pollution is its population...

環境保護主義者說造成該城市污染問題的一個關鍵因素是其人口數量。

b、(局勢)嚴重的，有危險的

The German authorities are considering an airlift if the situation becomes critical.

如果局勢變得危急，德國當局將考慮實施空運。

Its day-to-day finances are in a critical state.

其日常財務狀況十分糟糕。

c、批評的;挑剔的

His report is highly critical of the trial judge.

他在報告中對主審法官有頗多批評。

a few dozen intellectuals who've been critical of the regime.

幾十名一直批判該政權的知識分子