I. Clinical symptoms: 1. dyspnea: exertional dyspnea and progressive aggravation, shallow breathing, nasal agitation and auxiliary muscles may be involved in breathing, but mostly no telescopic breathing. 2. Cough and sputum: cough is more common, mainly dry cough or a small amount of mucus sputum. If secondary infection occurs, mucopurulent sputum may appear, and occasionally bloody sputum is seen. 3. Systemic symptoms: wasting, weakness, loss of appetite, joint pain, etc. may be present. 2. Common signs: 1. dyspnea and cyanosis. 2. Thoracic dilatation and decreased diaphragm mobility. 3.Velcro rales (popping sounds) in the lower and middle parts of both lungs with some specificity. 4.Pestle-shaped fingers (toes). 5, End-stage respiratory failure and right heart failure may appear corresponding signs.