As blood flows through the pulmonary capillaries, oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar gas.

当血液流过肺毛细血管时，氧气扩散到血液中，二氧化碳扩散到肺泡气体中。

Since the partial pressure of oxygen is lower in the blood entering the lungs than it is in the alveolar gas, oxygen diffuses into the blood.

由于进入肺部的血液中的氧分压低于肺泡气体中的氧分压，因此氧气扩散到血液中。

As air moves into the alveoli, water vapor and carbon dioxide are added, and that reduces the partial pressure of oxygen to about 100 mmHg in the alveolar gas.

当空气进入肺泡时，水蒸气和二氧化碳被加入其中，这使得肺泡气体中的氧分压降低到大约100 mmHg。

As carbon dioxide diffuses out of the blood into the alveolar gas, its concentration decreases in the blood and the reaction is pulled to the left, thus producing more carbon dioxide.

随着二氧化碳从血液中扩散到肺泡气体中，其浓度在血液中降低，反应被拉向左侧，从而产生更多的二氧化碳。