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  3. Drugs can be divided into three main groups: those that a person can buy without a prescription, those that a person needs a doc

Drugs can be divided into three main groups: those that a person can buy without a prescription, those that a person needs a doc

admin2010-09-10  33
问题     Drugs can be divided into three main groups: those that a person can buy without a prescription, those that a person needs a doctor’s prescription for, and those that are illegal.
    Two popular nonprescription drugs are caffeine (咖啡因) and alcohol. Caffeine is found in coffee, tea, chocolate, and cola drinks. It is a mental stimulant; it stimulates the central nervous system and makes people feel alert. Students, for example, often find they can study better if they have a cup of coffee. On the other hand, caffeine can also make people nervous and irritable. If people drink too much caffeine, they may have trouble sleeping.
    Alcohol is a depressant; it depresses the central nervous system. When people drink, they have less control over their actions. They cannot walk in a straight line and they cannot drive as well as when they are alcohol-free in their blood. People who drink a great deal sometimes fall into a deep sleep. Later, they may wake up with a strong headache.
     In addition to these nonprescription drugs, there are two major categories of prescription drugs: stimulants and depressants. The depressants include morphine(吗啡), which is used as a pain killer. The most common stimulants are amphetamines (苯丙胺). Doctors used to prescribe amphetamines as diet pills; however, they found that amphetamines can have serious side effects. They can make a patient very nervous, and when the drug wears off, the patient may feel very depressed. Doctors still give amphetamines  to people with narcolepsy, an illness that causes sudden, uncontrollable attacks of sleep.
    The largest class of illegal drugs are hallucinogens, drugs that change the way a person thinks and cause hallucinations, or visions. For some people, marijuana(大麻) is a mild hallucinogen. Marijuana generally brings a pleasant feeling. However, when people smoke marijuana, they sometimes can not concentrate very well on their activities, such as their work or driving.
What is the reason that too much tea drinking makes people have trouble sleeping?
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答案Because tea contains caffeine。
解析 我们知道简答题提问通常有以下两类：一、用疑问代词who，what，which 的提问。这类词所问的一般是主语、宾语和表语部分，要求考生用名词、动名词或名词词组回答。二、用疑问副词when，why，where，how等的提问，这类问所问的部分一般是状语部分，如时间、地点，方式等等。对疑问副词why 的提问应该用原囚状语回答比较稳妥。
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