Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient world slept only 6.5 hours a night.

尽管巴拿马在许多问题上与美国密切合作，但鲁比奥的访问旨在向外界传达白宫不会容忍中国在“美国后院”投资。据报导 ...