1、vital

a、必要的;至关重要的;必不可少的

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

这个港口对向数百万旱灾灾民提供救援物资是至关重要的。

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

尼克·威尔曼是学校的管理员，因此与年轻人搞好关系很重要。

b、充满活力的;生气勃勃的

They are both very vital people and a good match.

他俩都很有活力，十分般配。

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

他们有些重要的事情要说，言辞会比较激烈。

2、critical

a、极重要的;关键的

The incident happened at a critical point in the campaign.

该事件发生在竞选活动的关键时期。

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

环境保护主义者说造成该城市污染问题的一个关键因素是其人口数量。

b、(局势)严重的，有危险的

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

如果局势变得危急，德国当局将考虑实施空运。

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

其日常财务状况十分糟糕。

c、批评的;挑剔的

His report is highly critical of the trial judge.

他在报告中对主审法官有颇多批评。

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

几十名一直批判该政权的知识分子