【正文】 to approach disastrous proportions when, in 1888, the first mercially successful electric traction line was developed. Within a few years the horsedrawn trolleys were 在線英語聽力室 16 retired and electric streetcar works crisscrossed and connected every major urban area, fostering a wave of suburbanization that transformed the pact industrial city into a dispersed metropolis. This first phase of massscale suburbanization was reinforced by the simultaneous emergence of the urban Middle Class, whose desires for homeownership in neighborhoods far from the aging inner city were satisfied by the developers of singlefamily housing tracts. 10 Types of Speech Standard usage includes those words and expressions understood, used, and accepted by a majority of the speakers of a language in any situation regardless of the level of formality. As such, these words and expressions are well defined and listed in standard dictionaries. Colloquialisms, on the other hand, are familiar words and idioms that are understood by almost all speakers of a language and used in informal speech or writing, but not considered appropriate for more formal situations. Almost all idiomatic expressions 在線英語聽力室 17 are colloquial language. Slang, however, refers to words and expressions understood by a large number of speakers but not accepted as good, formal usage by the majority. Colloquial expressions and even slang may be found in standard dictionaries but will be so identified. Both colloquial usage and slang are more mon in speech than in writing. Colloquial speech often passes into standard speech. Some slang also passes into standard speech, but other slang expressions enjoy momentary popularity followed by obscurity. In some cases, the majority never accepts certain slang phrases but nevertheless retains them in their collective memories. Every generation seems to require its own set of words to describe familiar objects and events. It has been pointed out by a number of linguists that three cultural conditions are necessary for the creation of a large body of slang expressions. First, the introduction and acceptance of new objects and situations in the society。s generosity. His contributions of more than five million dollars established 2,500 libraries in small munities throughout the country and formed the nucleus of the public library system that we all enjoy today. 08 American Revolution The American Revolution was not a sudden and violent overturning of the political and social framework, such as later occurred in France and Russia, when both were already independent nations. Significant changes were ushered in, but they were not breathtaking. What happened was accelerated evolution rather than outright revolution. During the conflict itself people went on working and praying, marrying and playing. Most of them were not seriously disturbed by the actual fighting, and many of the more isolated munities scarcely knew that a war was on. America39。 they form an electrocardiogram, which a doctor can study to determine how well the heart is working. The brain, too, sends out brain waves of electricity, which can be recorded in an 在線英語聽力室 7 electroencephalogram. The electric currents generated by most living cells are extremely small – often so small that sensitive instruments are needed to record them. But in some animals, certain muscle cells have bee so specialized as electrical generators that they do not work as muscle cells at all. When large numbers of these cell are linked together, the effects can be astonishing. The electric eel is an amazing storage battery. It can seed a jolt of as much as eight hundred volts of electricity through the water in which it live. ( An electric house current is only one hundred twenty volts.) As many as fourfifths of all the cells in the electric eel’s body are specialized for generating electricity, and the strength of the shock it can deliver corresponds roughly to length of its body. 05 The Beginning of Drama There are many theories about the beginning of drama in ancient Greece. The on most widely accepted today is based on the assumption that drama evolved from ritual. The 在線英語聽力室 8 argument for this view goes as follows. In the beginning, human beings viewed the natural forces of the worldeven the seasonal changesas unpredictable, and they sought through various means to control these unknown and feared powers. Those measures which appeared to bring the desired results were then retained and repeated until they hardened into fixed rituals. Eventually stories arose which explained or veiled the mysteries of the rites. As time passed some rituals were abandoned, but the stories, later called myths, persisted and provided material for art and drama. Those who believe that drama evolved out of ritual also argue that those rites contained the seed of theater because music, dance, masks, and costumes were almost always used, Furthermore, a suitable site had to be provided for performances and when the entire munity did not participate, a clear division was usually made between the acting area and the auditorium. In addition, there were performers, and, since considerable importance was attached to avoiding mistakes in the enactment of rites, religious leaders usually assumed that task. Wearing masks and costumes, they often impersonated other people, animals, or 在線英語聽力室 9 supernatural beings, and mimed the desired effectsuccess in hunt or battle, the ing rain, the revival of the Sunas an actor might. Eventually such dramatic representations were separated from religious activities. Another theory traces the theater39。在線英語聽力室 1 01 The Language of Music A painter hangs his or her finished