Background Paragraph: Pulmonary fibrosis (literally "scarring of the lungs") is a respiratory disease in which scars are formed in the lung tissues, leading to serious breathing problems. Scar formation, the accumulation of excess fibrous connective tissue (the process called fibrosis), leads to thickening of the walls, and causes reduced oxygen supply in the blood. As a consequence patients suffer from perpetual shortness of breath.[1]. 
Story: Air pollution is a big problem in large industrial cities. New York has its share or air pollution. John is a doctor who works for a New York hospital. Today, he is seeing two patients, patient A and patient B. His diagnosis revealed that patient A has pulmonary fibrosis, but patient B does not have pulmonary fibrosis.
In which patient John didn't find thickening of lung walls, patient A or patient B? In which patient John found thickening of lung walls, patient A or patient B? In which patient John would not observe scarred lung tissues? In which patient John would observe scarred lung tissues? Were patient A's lung walls thickened or not thickened? Were patient B's lung walls thickened or not thickened? Which patient should be worried about reduced oxygen supply in the blood? Which patient should not be worried about reduced oxygen supply in the blood? Would patient A have reduced or normal oxygen supply in the blood? Would patient B have reduced or normal oxygen supply in the blood?