life-and-death
adjective [ before noun ] uk/ˌlaɪf.ənˈdeθ/ us/ˌlaɪf.ənˈdeθ/ (also life-or-death)
生死攸关的（有人可能会丧生的）
involving the possibility that someone will die
We were now in a life-and-death situation. 我们现在处于生死攸关的情形下。
生死攸关的（非常重要的，非常严肃的）
very important and serious
a life-and-death matter 生死攸关的事