人类最初的飞行梦想诞生于何时,这无从考证,但人类对飞行的尝试却从未间断。鸟儿好像飞得很容易,它们为了捕食而疾飞,还能飞过森林、河流那样的障碍。许多昆虫也是这样。鸟儿骨头轻,翅膀上覆盖着羽毛,身体里分布着气囊,但人类却有一个问题:与鸟儿相比,人的身体结构不适于飞翔。 It is impossible to verify when the first flight dream of mankind was born, but mankind’s flight attempt has never stopped. Birds seem to fly very easily, they flew for predation and flew over obstacles like forests and rivers. The same is true for many insects. Bird bones light, wings covered with feathers, airbags distributed in the body, but humans have a problem: compared with the birds, the human body structure is not suitable for flying.