Introduction "When supply exceeds demand,price decreases;when demand e exceeds supply,price increases."We knew this principle when we were in middle school. But this principle is not unconditional. Price can be influenced by some other factors,and sometimes the supply and demand relationship does not work. 制尔香行質易大孝Introduction Introduction “When supply exceeds demand, price When supply exceeds demand, price decreases; when demand exceeds decreases; when demand exceeds supply, price increases. supply, price increases.” ” We knew this We knew this principle when we were in middle school. principle when we were in middle school. But this principle is not unconditional. But this principle is not unconditional. Price can be influenced by some other Price can be influenced by some other factors, and sometimes the supply and factors, and sometimes the supply and demand relationship does not work. demand relationship does not work