In general, the severity of pneumonia is judged by the following aspects: 1. clinical manifestations, the more serious signs are obvious severe cough, coughing sputum, a large amount of purulent sputum with hemoptysis, and severe chest pain, chest tightness, and even accompanied by respiratory distress, respiratory failure, and the patient slightly strenuous activity or heavy physical activity, it is obvious that the symptoms of respiratory distress increased. 2. X-ray or CT of both lungs can show obvious infiltrative foci, which may be accompanied by compensatory emphysema, pulmonary atelectasis, mediastinal emphysema, etc. In severe cases, different degrees of cavities can be seen at the foci, and there are fluid planes inside suggesting the formation of lung abscess. 3. Pulmonary function tests can clearly show a moderate to severe decrease in lung function.