The nymphs of the periodical cicada have been biding their time. 布鲁德X蝉(一种周期蝉)的若虫 为这个机会等待了很长时间

156. but tonight is special.
     不过今晚非常特别
157. After seventeen years underground
     在17年的地下潜伏后
158. creatures are stirring.
     一种生物开始活跃起来
159. The nymphs of the periodical cicada have been biding their time.
     布鲁德X蝉(一种周期蝉)的若虫 为这个机会等待了很长时间
160. Now they march like zombies towards the nearest tree, and start to climb.
     现在它们如朝圣般向最近的树进军 并开始攀爬
161. At first, there are merely thousands
     一开始,不过几千只
162. but soon, more than a billion swarm all over the forest.
     马上,10亿只若虫爬满了整个森林

来自《行星地球 第一季 第十集 Planet Earth S01E10 季节森林》第 159 行