If you cough up mucus that's any other color than clear, that can be a sign your condition is worsening, says Byron Thomashow of Columbia and the COPD Foundation.
如果你咳出的痰液颜色是非透明的，那是你状况恶化的标志，COPD基金会，哥伦比亚的拜伦·托马斯休说。
2
The problem with this, Thomashow says, is that the lung damage that constitutes COPD can't be reversed; all you can do is halt or slow the progression of the disease.