As lung diseases are becoming more and more prevalent due to the environment and living habits nowadays, lung examinations appear to be necessary. 1. check the capacity of the lungs, different people breathe differently and have different lung volumes. 2. check the ventilation of the lungs to see if the function of ventilation is normal when the lungs inhale and expel air. 3. check the regulation function of breathing to see if the lungs are healthy. 4. To see if the lungs are healthy. 4. To check the circulatory capacity of the lungs, to see if the lungs are normal when storing blood. 5. To check the total amount of gas after the lungs inhale, to see if it is in the normal range. 6. To check the small airways, to have a positive effect on the discovery of lesions in the lungs. 7.