黎巴嫩首都爆炸已致135死

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2025小年夜，一起开新向未来！。NOVA: Mysteries of Sleep Like virtually every other animal, humans need sleep to survive. But why? What do we gain from spending nearly a third of our lives in such a defenseless state? And what's at stake if we sleep poorly? The functions of sleep have long been something of a mystery. But now scientists are peering deep into the brain to see what happens while we snooze. One ...。