•This illness is fatal in almost all cases.这种病几乎是不治之症。

•the fatal shooting of an unarmed 15-year-old对手无寸铁的15岁少年的致命枪击

•He made the fatal mistake/error of believing what they told him.他听信了他们的话，犯了灾难性的错误。

•It just shows how you should never say how well things are going for you - it's fatal (= it causes bad things to happen).这件事恰恰说明你决不能说事情进展很顺利——这么讲会带来大麻烦。