单选题 Technically, any substance other than food that alters our bodily or mental functioning is a drug. Many people mistakenly believe the term drug refers only to some sort of medicine or an illegal chemical taken by drug addicts. They don"t realize that familiar substances such as alcohol and tobacco are also drugs. This is why the more neutral term substance is now used by many physicians and psychologists. The phrase "substance abuse" is often used instead of "drug abuse" to make clear that substances such as alcohol and tobacco can be just as harmfully misused as heroin and cocaine.
We live a society in which the medicinal and social use of substances (drugs) is pervasive: an aspirin to quiet a headache, some wine to be sociable, coffee to get going in the morning, a cigarette for the nerves. When do these socially acceptable and apparently constructive uses of a substance become misuses? First of all, most substances taken in excess will produce negative effects such as poisoning or intense perceptual distortions. Repeated use of a substance can also lead to physical addiction or substance dependence. Dependence is marked first by an increased tolerance, with more and more of the substance required to produce the desired effect, and then by the appearance of unpleasant withdrawal symptoms when the substance is discontinued.
Drugs (substances) that affect the central nervous system and alter perception, mood, and behavior are known as psychoactive substances. Psychoactive substances are commonly grouped according to whether they are stimulants, depressants, or hallucinogens. Stimulants initially speed up or activate the central nervous system, whereas depressants slow it down. Hallucinogens have their primary effect on perception, distorting and altering it in a variety of ways including producing hallucinations. These are the substances often called psychedelic (from the Greek word meaning "mind manifesting") because they seemed to radically alter one"s state of consciousness.

单选题 "Substance abuse" (Line 5, Para. 1) is preferable to "drug abuse" in that______.

【正确答案】 D

【答案解析】[解析] 本题可参照文章的第1段。从中可知，从技术的角度讲，除食品外，任何能改变我们生理或心理机能的物质都是药物；许多人错误地认为，药物这个词只指某些药品或嗜毒者服用的违禁化学药品，他们没有意识到像酒精和烟草这类常见物质也是药物；医生和心理学家们经常用“物质滥用”取代“药物滥用”，来明确表明像酒精和烟草这样的物质也会像海洛因和可卡因一样因滥用而造成危害。据此可知，能够对人造成伤害的不只是海洛因和可卡因这类药物，其他许多物质都可以对人造成伤害。D项与文章的意思相符；A项与文章第1段第2句话的意思不符；B项与文章第1段第2、3句话的意思不符；C项不正确，文章只是说“酒精和烟草也能像海洛因和可卡因一样因滥用而对人造成危害”，并没有说使人致命。综上所述，只有D项为正确答案。

单选题 The word "pervasive" (Line 1, Para. 2) might mean ______.

【正确答案】 A

【答案解析】[解析] 本题可参照文章第2段的第1句话。从中可知，在我们生活的社会，物质(药物)被广泛地应用于社交和医疗——服用阿司匹林以减缓头痛，喝点酒以增进友谊，早上喝咖啡以提神，吸烟以消除紧张情绪。据此可知，阿司匹林、酒、咖啡和烟等都是常用物品，因此“pervasive”的意思应该是“使用广泛的”。因此A项为正确答案。

单选题 Physical dependence on certain substances results from ______.

【正确答案】 A

【答案解析】[解析] 本题可参照文章第2段的倒数两句话。从中可知，反复使用一种物质也会导致对该物质的生理上瘾或对药物依赖；依赖性起初表现为耐受性不断增强，需要越来越多的药物才能获得所需的效果，一旦停用，就会产生不舒服的症状。据此可知，对某些物质的生理依赖，是由于人们长时间、大量使用这些物质所造成的。A项与文章的意思相符；B项不正确，文中是说“喝一点酒以增进友谊”，但并没有说这会导致对酒的生理依赖；C项和D项明显不是对某些物质生理依赖的原因。综上所述，只有A项为正确答案。

单选题 From the last paragraph we can infer that ______.

【正确答案】 B

【答案解析】[解析] 从文章最后一段的内容可知，通过影响中枢神经系统来改变人的感觉、情绪和行为的药物(物质)被称作精神活性物质；这类物质一般分为兴奋剂、镇静剂和幻觉剂；兴奋剂主要有加快或激活中枢神经系统的作用，而镇静剂却刚好于之相反：使其减缓；幻觉剂主要作用于人的感觉，以多种方式(包括制造幻觉)扭曲和改变知觉；这些就是通常被称作迷幻剂的物质，因为它们似乎彻底改变了一个人的意识状态。据此可知，在三种对神经系统起作用的物质中，兴奋剂和镇静剂影响人的中枢神经系统，而幻觉剂却改变人的知觉、情绪和行为，显然对人的身体更有害。B项与文章的意思相符；A项不正确，文中是说“兴奋剂主要有加快或激活中枢神经系统的作用”，并没有说对智力有影响；文中没有提到C项；D项不正确，文中是说“兴奋剂主要有加快或激活中枢神经系统的作用，而镇静剂却刚好于之相反：使其减缓，幻觉剂主要作用于人的感觉”，并没有说把三种对神经系统起作用的物质一起使用。综上所述，只有B项为正确答案。