1. The American economic system is organized around a basically private enterprise, marketoriented economy in which consumers largely determine what shall be produced by spending their money in the marketplace for those goods and services that they want most. Private businessmen, striving to make profits, produce these goods and services in competition with other businessmen; and the profit motive, operating under competitive pressures, largely determines how these goods and services are produce. ____________________.
[A] Thus, in the American economic system it is the demand of individual consumer, coupled with the desire of businessmen to maximize profits and the desire of individuals to maximize their incomes, that together determine what shall be produced and how resources are used to produce it.
[B] In the American economy, this mechanism is provided by a price system, a process in which prices rise and fall in response to relative demands of consumers and supplies offered by seller producers.

【答案】[A]。空格前具体介绍了影响美国经济体制的几点因素。分析[A]、[B]两选项，[A]恰好从这几方面对以上内容加以总结，故为答案；[B]中主要是说供与求决定价格，它并不是影响美国经济体制的因素，放在此处显然与上文没有必然的联系。
2. ___________________. Electronic cash registers can do much more than simply ring up sales. They can keep a wide range of records, including who sold what, when, and to whom. This information allows businessmen to keep track of their list of goods by showing which items are being sold and how fast they are moving. Decisions to reorder or return goods to suppliers can then be made. At the same time these computers record which hours are busiest and which employees are the most efficient, allowing personnel and staffing assignments to be made accordingly. And they also identify preferred customers for promotional campaigns. Computers are relied on by manufacturers for similar reasons.
[A] Numerous other commercial enterprises, from theaters to magazine publishers, from gas and electric utilities to milk processors, bring better and more efficient services to consumers through the use of computers.
[B] While computers offer these conveniences to consumers, they have many advantages
for sellers too.

【答案】[B]。空格后面的所有内容都是关于计算机给"businessmen"带来方便的描述，所以空格处也应与此有关。[B]中提到了计算机给"consumers"和"seller"双方面带来的方便，但显然此句强调的是后者，而这正是对下文的总结，故为答案；[A]只是概括性的描述计算机给"consumers"带来的各方面的利益，与"businessmen"无关。
3. ____________________. The researchers made great progress in the early 1970s,when they discovered that oncogenes, which are cancer causing genes (基因), are inactive in normal cells. Anything from cosmic rays to radiation to diet may activate a dormant oncogene, but how remains unknown. If several oncogenes are driven into action, the cell, unable to turn them off, becomes cancerous.
[A] The exact mechanisms involved are still mysterious, but the likelihood that many cancers are initiated at the level of genes suggests that we will never prevent all cancers.
[B] With as many as 120 varieties in existence, discovering how cancer works is not easy.

【答案】[B]。空格后说"致癌基因在正常细胞中并不活跃，如果几个被激活，而细胞不能将它们排除，它们才会变成癌变细胞"，可见所述内容是关于癌症的产生，所以空格处的语言也应与此有关。[B]中的"how cancer works"恰好是后面所有内容的总结，符合题意。[A]主要是强调that引导的宾语从句中的内容，即"我们无法阻止所有癌症的产生"，但并没有提到癌症是怎样产生的，所以相对而言，[B]更合适。
4. ____________________. Innovators will not accept that there is only one way to do anything. Faced with getting from A to B, the average person will automatically set out on the best-known and apparently simplest route. The innovator will search for alternate courses, which may prove easier in the long run and are bound to be more interesting and challenging even if they lead to dead ends.
[A] The creative approach begins with the proposition that nothing is as it appears.
[B] Highly creative individuals really do march to a different drummer.

【答案】[A]。[A]中主要内容是关于"creative approach"的，空格后说有创造力的人的主要特点就是他们不随波逐流，而总是找寻新的做事方法，正好与[A]中的"nothing is as it appears"的方法相稳合。而[B]的意思是"有创造性的人伴随着不同的鼓点的节奏前进"，它显然是一个高度概括的句子，但放在此处不够明确，前后衔接也不恰当。
5. ____________________. It serves directly to assist a rapid distribution of goods at reasonable price, thereby establishing a firm home market and so making it possible to provide for export at competitive prices. By drawing attention to new ideas it helps enormously to raise standards of living. By helping to increase demand it ensures an increased need for labour, and is therefore an effective way to fight unemployment. It lowers the costs of many services: without advertisements your daily newspaper would cost four times as much, the price of your television licence would need to be doubled, and travel by bus or tube would cost 20 per cent more.
[A] Money spent on advertising is money spent as well as any I know of.
[B] Advertising does more for the material benefit of the community than any other force
I can think of.

【答案】[A]。此题的两个选项具有很强的迷惑性，感觉意思差不多，不好区分，但还是有细微的差别。[A]的意思是"花钱做广告是我所知道的最好的花钱方式之一"，下文具体地解释广告具有怎样的好处，来证明花钱做广告是值得的，前后衔接连贯；[B]的意思是"广告给社会带来的物质利益比任何我所能想到的方式都多"，它肯定了广告给社会带来的利益，但强调的是有更多的利益是我所没想到的，如果把这句话放在空格处，而后面又列出了作者能想到的广告的好处，显然前后矛盾。
6. ____________________. Computer technology makes it possible to store vast amounts of data in machine readable files, and to program computers to locate specific information. Telecommunications developments enable the sending of messages via television, radio, and very shortly, electronic mail to bombard people with multitudes of messages. Satellites have extended the power of communications to report events at the instant of occurrence. Expertise can be shared worldwide through teleconferencing, and problems in dispute can be settled without the participants leaving their homes and/or jobs to travel to a distant conference site.
[A] Adding to societal changes today is an enormous stockpile of information. The individual now has more information available than any generation, and the task of finding that one piece of information relevant to his or her specific problem is complicated, time-consuming and sometimes even overwhelming.
[B] Coupled with the growing quantity of information is the development of technologies which enable the storage and delivery of more information with greater speed to
more locations than has ever been possible before.

【答案】[B]。对"技术"作用的阐述是空格后的例子所要说明的问题。[A]的主要内容是关于"enormous stockpile of information"的，与"technology"关系不够直接；[B]用了"coupled with"提出了两方面的内容："quantity of information"和"development of technologies"，应该说是对这一段主旨的概括，故正确。
7. Practice (or review) tends to build and maintain memory for a task or for any learned material. Over a period of no practice what has been learned tends to be forgotten; and the adaptive consequences may not seem obvious. Yet, dramatic instances of sudden forgetting can be seen to be adaptive. In this sense, the ability to forget can be interpreted to have survived through a process of natural selection in animals. Indeed, when one's memory of an emotionally painful experience lead to serious anxiety, forgetting may produce relief. Nevertheless, an evolutionary interpretation might make it difficult to understand how the commonlygradual process of forgetting survived natural selection.
____________________. Forgetting clearly aids orientation in time, since old memories weaken and the new tend to stand out, providing clues for inferring duration. Without forgetting, adaptive ability would suffer, for example, learned behaviour that might have been correct a decade ago may no longer be. Cases are recorded of people who (by ordinary standards) forgot so little that their everyday activities were full of confusion. This forgetting seems to serve that survival of the individual and the species.
[A] In thinking about the evolution of memory together with all its possible aspects, it is helpful to consider what would happen if memories failed to fade.
[B] In this view, continual adjustments are made between learning or memory storage
(input) and forgetting (output).

【答案】[A]。空格前一段指出遗忘是进化的结果，空格后说的是遗忘的重要性。观察两个备选项：[A]中"what would happen if memories failed to fade"正好与下文的解释一致，所以应为答案；把原文内容与选项[B]的内容进行对比，感觉[B]不应该放在本段的开头，放在此段的结尾更合适，因为它更像是对整段内容的总结。