they must cross the Himalayas. 它们必须跨越喜马拉雅山脉

288. The Nepalese call it 'a mountain so high no bird can fly above it.'
     尼泊尔人称之为 “一座高得连鸟也飞不上去的山峰”
289. 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
290. To reach their overwintering grounds in India
     要想到达印度境内的越冬场所
291. they must cross the Himalayas.
     它们必须跨越喜马拉雅山脉
292. By late morning ferocious winds are roaring past the peaks.
     晌午时分 群山间狂风大作
293. The cranes must gain height to avoid the building storm.
     鹤群必须提升高度 躲避正在形成的风暴
294. They've hit serious turbulence.
     它们遇上了一股强力气旋

来自《行星地球 第一季 第二集 Planet Earth S01E02 山地》第 291 行