最 + 致命 + 的 + Noun
The adjective 致命 (zhìmìng) means "fatal" or "deadly" and describes something that can cause or has caused death. It is often used with 最 (most) to indicate the deadliest instance of something, as in 最致命的事件 (the deadliest incident).
这种病毒对老年人来说可能是致命的。
zhè zhǒng bìngdú duì lǎoniánrén lái shuō kěnéng shì zhìmìng de.
This virus can be fatal for elderly people.
司机犯了一个致命的错误,没有注意红灯。
sījī fàn le yí ge zhìmìng de cuòwù, méiyǒu zhùyì hóngdēng.
The driver made a fatal mistake by not noticing the red light.
高温天气对农作物造成了致命的影响。
gāowēn tiānqì duì nóngzuòwù zàochéng le zhìmìng de yǐngxiǎng.
The extreme heat has had a devastating impact on crops.