听力原文： A heroin addiction today is found chiefly among young men of minority groups in ghetto areas. Of the more than 60, 000 known addicts, more than half live in New York State. Most of them live in New York City. Recent figures show that more than haft of the addicts are under 30 years of age. Narcotic addiction in the United States is not limited to heroin users. Some middle-aged and older people who take narcotic drugs regularly to relieve pain can also become addicted. So do some people who can get drugs easily, such as doctors, nurses, and pharmacists. Studies show that this type of addict has personality and emotional problems very similar to those of other regular narcotic users. Many addicts admit that getting a continued supply is the main object of their lives. An addict’s concentration on get ting drugs often prevents continuing an education or working at a job. His health is often poor. He may be sick one day from the effects of withdrawal and sick the next day from an overdose. Statistics show that an addict’s life span may be shortened by 15 to 20 years. The addict is usually in trouble with the family and almost always in trouble with the law. What prevents a drug addict from continuing his education or taking at a job?