[单项选择]It is common knowledge that drug abuse leads to harmful consequences. Why then do people—particularly youngsters—continue to use drugs
Psychologists claim that there are three basic motivations that influence people to take drugs: curiosity, stress and environmental factors. Sometimes, youngsters take drugs simply because they are curious. Taking drugs seems to be the "in thing" for their generation, so they want to know what drugs are like. The trouble is that they do not know that taking soft and seemingly unharmful drugs can develop into cravings for stronger stuff later on. In some cases, youngsters are depressed or frustrated because of problems related to parents, school or the opposite sex. They take drugs to escape from the stress brought on by all these problems. In other cases, the environment is conductive to taking drugs. If, for instance, a youngster belongs to a community, school, or peer group where other youngsters take drugs, he may soon be tempted to follow suit,
A. Curiosity.
B. Fashion.
C. Necessity.
D. Pressure.

[单项选择]It is common knowledge that drug abuse leads to harmful consequences. Why then do people—particularly youngsters—continue to use drugs
Psychologists claim that there are three basic motivations that influence people to take drugs: curiosity, stress and environmental factors. Sometimes, youngsters take drugs simply because they are curious. Taking drugs seems to be the "in thing" for their generation, so they want to know what drugs are like. The trouble is that they do not know that taking soft and seemingly unharmful drugs can develop into cravings for stronger stuff later on. In some cases, youngsters are depressed or frustrated because of problems related to parents, school or the opposite sex. They take drugs to escape from the stress brought on by all these problems. In other cases, the environment is conductive to taking drugs. If, for instance, a youngster belongs to a community, school, or peer group where other youngsters take drugs, he may soon be tempted to follow suit,
A. They think that soft drugs are not harmful.
B. They wonder what drugs are like.
C. They are disturbed by problems.
D. Their parents are drug takers.

[单项选择]Drug abuse can cause a wide variety of adverse physical reactions. Long-term drug use may (67) the heart, liver, and brain. Drug abusers may suffer from (68) if they habitually forget to eat, (69) afford to buy food, or eat foods (70) the proper vitamins and minerals. Individuals who abuse injectable drugs risk (71) infections such as hepatitis and HIV from dirty needles or needles shared with other (72) abusers. One of the most dangerous effects of (73) drug use is the potential for overdosing -- (74) is, taking too large or too strong a dose for the body’s systems to handle. A drug overdose may cause an individual to lose (75) and to breathe inadequately. Without treatment, an individual may die (76) a drug overdose.
Drug (77) is marked by an irresistible thirst (78) a substance. Successful treatment methods vary and include psychological counseling, or psychotherapy, and