肺泡

例句：

1. 1.The lungs are made up of millions of tiny air sacs called alveoli.
   肺部由数百万个被称为肺泡的微小空气囊组成。
2. 2. During sleep, the alveoli in the lungs expand to allow more oxygen to reach the bloodstream.
   在睡眠时，肺部的肺泡会扩张以允许更多的氧气到达血液。
3. 3. As we breathe in and out, our lungs fill with air and release it back into the atmosphere.
   当我们吸气和呼气时，我们的肺部充满空气并释放到大气中。