It creates some local damage, and then works its way down the respiratory tree kind of like a secret agent rappelling down a rope of mucus.

病毒在这里造成一定局部损伤后继续向下进入肺部支气管，有点像特工抓着黏液的绳子下降。

Rhythmically contracting and relaxing their muscles, they draw water in and out over an internal lung-like structure called a respiratory tree that extracts oxygen from seawater.

它们有节奏地收缩和放松肌肉，通过称为呼吸树的内部肺状结构吸入和排出水，呼吸树从海水中提取氧气。