单项选择题

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 in 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. The word" pervasive’’ ( Line 1, Paragraph 2) might mean___________.

A．widespread
B．overwhelming
C．piercing
D．fashionable
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Comparisons were drawn between the development of television in the 20th century and the diffusion of printing in the 15th and 16th centuries. Yet much had happened ________As was discussed before, it was not ______ the 19th century that the newspaper became the dominant pre- electronic ______ , following in the wake of the pamphlet and the book and in the________of the periodical. It was during the same time that the communications revolution________ up, beginning with transport, the railway, and leading________ through the telegraph, the telephone, radio, and motion pictures________ the 20th-century world of the motor car and the airplane. Not everyone sees that process in________ It is important to do so.It is generally recognized,________ , that the introduction of the computer in the early 20th century,________by the invention of the integrated circuit during the 1960s, radically changed the process,________its impact on the media was not immediately________As time went by, computers became smaller and more powerful, and they became personal too, as well as________, with display becoming sharper and storage________increasing. They were thought of, like people,________generations, with the distance between generations much________.It was within the computer age that the term information society began to be widely used to describe the________within which we now live. The communications revolution has________both work and leisure and how we think and feel both about place and time, but there have been________views about its economic, political, social and cultural implications. Benefits have been weighed________ harmful outcomes. And generalizations have proved difficult.
单项选择题
Substance abuse ( Line 5, Paragraph 1 ) is preferable to drug abuse in that ___________.
A．substances can alter our bodily or mental functioning if illegally used
B．"drug abuse" is only related to a limited number of drug takers
C．alcohol and tobacco are as fatal as heroin and cocaine
D．many substances other than heroin or cocaine can also be poisonous
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