As is true of any developed society, in America a complex set of cultural signals, assumptions, and conventions underlies all social interrelationships. And, of course, speaking a language does not necessarily meant that someone understands social and cultural patterns. Visitors who fail to"translate"cultural meanings properly often draw wrong conclusions. For example, when an American uses the word"friend", the cultural implications of the word may be quite different from those it has in the visitor's language and culture. It takes more than a brief encounter on a bus to distinguish between courteous convention and individual interest. Yet, being friendly is a virtue that many American value highly and expect from both neighbors and strangers.

　　55.In the eyes of visitors from the outside world, _____.

　　A)rude taxi drivers are rarely seen in the US

　　B)small minded officials deserve a serious comment

　　C)Canadians are not so friendly as their neighbors

　　D)most Americans are ready to offer help

　　56.It could be inferred from the last paragraph that _____.

　　A)culture exercises an influence over social interrelationship

　　B)courteous convention and individual interest are interrelated

　　C)various virtues manifest themselves exclusively among friends

　　D)social interrelationships equal the complex set of cultural conventions

　　57.Families in frontier settlements used to entertain strangers _____.

　　A)to improve their hard life

　　B)in view of their long distance travel

　　C)to add some flavor to their own daily life

　　D)out of a charitable impulse

　　58.The tradition of hospitality to strangers _____.

　　A)tends to be superficial and artificial

　　B)is generally well kept up in the United States

　　C)is always understood properly

　　D)was something to do with the busy tourist trails

　　Passage 3

　　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.