each trimmed to the correct length, 每一根修剪到合适的长度

167. He's grown elaborate breeding plumage for this moment,
     为此他已长出漂亮的繁殖羽
168. but he needs a stage on which to show it off.
     但他需要舞台来展现自我
169. By carefully selecting grass blades,
     细心挑选草茎
170. each trimmed to the correct length,
     每一根修剪到合适的长度
171. he's creating something very special.
     他正在进行非常独特的创作
172. He needs an even surface,
     他需要一块平地
173. and a centre-piece.
     和一个放在中央的装饰物

来自《行星地球 第二季 第五集 Planet Earth S02E05 草原》第 170 行