鸟的种类很多,在自然界中有着重要地位。它们不但维系着自然界的平衡,而且有些鸟类还给人以启示,从而引出发明创造,造福于人类。信天翁(图1)是一种大型海鸟,尤其是它的翅膀与身体的比例,与其他任何鸟类比起来都要显得长,翼展的宽度是身长的15倍。因此,它的翅膀扇动起来,升力非 Many species of birds have an important place in the natural world. They not only maintain the balance of the natural world, but some birds also give people inspiration, which leads to inventions and benefits for humanity. The albatross (Figure 1) is a large seabird, especially its wing-to-body ratio, which is longer than any other bird. The width of the wingspan is 15 times its length. As a result, its wings are flapped and lift is not