respiratory pathways

例句：

1. 1. The lungs are the primary respiratorypathways for oxygen and carbon dioxide exchange.
   肺部是氧气和二氧化碳交换的主要呼吸途径。
2. 2. The study of respiratory pathways is crucialfor understanding the functioning of the humanbody.
   研究呼吸途径对于理解人体功能至关重要。
3. 3. During sleep, the respiratory pathways becomemore relaxed, allowing for deeper breathing.
   在睡眠时，呼吸途径变得更加放松，允许更深入的呼吸。