生死存亡 [- - cún wánɡ](grave crisis between) life and death; critical; (a question of) life and death (for ...); of vital importance; survival or extinction:
•¶生死存亡的斗争 a life-and-death struggle
•¶ 中华民族到了这生死存亡的关头。 The Chinese nation has reached a point where its very existence is at stake.