he can now set off on the long journey home. 他开始漫长的归家旅程
that few humans have even set foot on them. 以至于几乎没有人类踏足
a different set of players begin to warm up. 各种声音又开始活跃起来
Thirty days after it last set, the sun rises once more on Antarctica. 南极洲的太阳在落山30天后 再次升起
But each year over 50,000 demoiselle cranes set out on one of the most challenging migrations on Earth. 可是 5万多只蓑羽鹤每年都会 进行一场地球上最具挑战性的迁徙