Dramatic declines in fertility rates in some countries and high rates in others pose a critical challenge.

有的国家生育率骤降，而有的国家生育率却居高不下，两种局面并存，人类面临着严峻的考验。

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Indeed, bleeding contributes to approximately 30% of trauma-related deaths. 1 bleeding in critical locations, such as an intracerebral hemorrhage, may also pose a major clinical challenge.

实际上，出血是大约30%的创伤死亡病例的死亡原因。1关键部位的出血，如脑出血，也临床面临的一项主要挑战。

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Indeed, bleeding contributes to approximately 30% of trauma-related deaths. 1 bleeding in critical locations, such as an intracerebral hemorrhage, may also pose a major clinical challenge.

实际上，出血是大约30%的创伤死亡病例的死亡原因。1关键部位的出血，如脑出血，也临床面临的一项主要挑战。

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