But once the sun sets, 但一旦太阳下山

193. grow on its upper slopes.
     生长在山顶斜坡上
194. They all thrive in the tropical sun.
     它们在炎炎烈日下茁壮成长
195. After all, every day is summer.
     毕竟赤道每天都是夏天
196. But once the sun sets,
     但一旦太阳下山
197. every night becomes as bitterly cold as winter.
     每个夜晚都像冬天般寒冷
198. The temperature drops to five degrees below freezing,
     气温降到零下五度
199. turning the mountainside into a garden of ice.
     山坡变成了冰雪花园

来自《行星地球 第二季 第二集 Planet Earth S02E02 山脉》第 196 行