A．It usually happens in urban areas.
B．It is known as a deadly disease for humans.
C．It could be prevented in many cases.
D．It can be cured in five to eight years.
A．The impact of smoking lasts less than 30 years.
B．Smoking has a long-term impact on Our molecular machinery.
C．Damages caused by smoking can never be cured.
D．Ailments are mainly caused by damage to the DNA.