【答案解析】[听力原文]
Health Hazards of Smoking
Tobacco is the leading cause of lung disease. / Studies have found that nicotine can be as powerful as alcohol. / Nicotine is a poison. / But it is also the major substance in cigarettes that gives pleasure to smokers. / When a former smoker smokes a cigarette, / the nicotine reaction may start again, / forcing the person to keep smoking. / So experts say it is better not to start smoking / and become dependent on nicotine than it is to smoke with the idea of stopping later.