3 sentences

1. 这是生死攸关的大事。

   zhè shì shēng​sǐ​yōu​guān de dà​shì.

   This is a matter of life and death.

   Source: OpenSubtitles

2. 此事生死攸关，千万不可大意。

   cǐ shì shēng​sǐ yōu guān, qiān​wàn bù kě dà yì.

   This is a matter of life and death; you must not be careless under any circumstances.

   Source: Dong Chinese Dictionary

3. 救援队在生死攸关的时刻，成功救出了所有受困者。

   jiù​yuán​duì zài shēng​sǐ​yōu​guān de shí​kè, chéng​gōng jiù​chū le suǒ​yǒu shòu​kùn​zhě.

   At a critical life-and-death moment, the rescue team successfully saved everyone who was trapped.

   Source: Dong Chinese Dictionary