1.Frequent colds, recurrent bronchitis and pneumonia. 2.Feeding difficulties or infants refuse to eat, choking and coughing, often eating and stopping, shortness of breath, pale face, breath-holding, etc. 3.The skin is continuously cyanotic, most obvious at the tip of the nose, lips of the mouth and finger (toe) nails. 4.Children who can walk will often crouch down voluntarily for a moment while walking or playing. 5.Older children have thickened and darkened finger and toe end segments. 6.Easy fatigue, poor stamina, excessive sweating in general, greening around the mouth, hemoptysis. 7, abnormal development, manifested as thinness, growth retardation, etc. 8.The child has chest pain and fainting.