阅读理解 Increasingly, historians are blaming diseases imported from the Old World for the big gap between the native population of America in 1492 new estimates of which jump as high as t00 million, or approximately one-sixth of the human race at that time -- and the few million full- blooded (纯血统的) Native Americans alive at the end of the nineteenth century. There. is no doubt that chronic disease was an important factor in the sharp decline, and it is highly probable that the greatest killer was epidemic disease, especially as manifested in virgin-soil epidemics. Virgin-soil epidemics are those in which the population at risk have had no previous contact with the diseases that strike them and are therefore immunologically (免疫学地) almost defenseless. That virgin-soil epidemics were important in American history is strongly indicated by evidence that a number of dangerous rnaladies (疾病) -- smallpox, measles, malaria, yellow fever, and undoubtedly several more were unknown in the pre-Columbian New World. The effects of their sudden introduction are demonstrated in the early chronicles (编年史)of America, which contain reports of horrible epidemics and steep population declines, confirmed in many cases by quantitative analyses of Spanish tribute records and other sources. The evidence provided by the documents of British and French colonies is not as definitive because the conquerors of those areas didn''t establish permanent settlements and began to keep continuous records until the seventeenth century, by which time the worst epidemics had probably already taken place. Furthermore, the British tended to drive the native populations away, rather than to enslave them as the Spaniards did, so that the epidemics of British America occurred beyond the range of colonists'' direct observation. Even so, the surviving records of North America do contain references to deadly epidemics among the native population. In 1616 — 1619 an epidemic, possibly of pneumonic plague, swept coastal New England, killing as many as nine out of ten.. During the 1630''s smallpox, the disease most fatal to the native American people, eliminated half the population of the Huron and Iroquois confederations. In the 1820''s fever ruined the people of the Columbia River area, killing eight out of ten of them. Unfortunately, the documentation of these and other epidemics is slight and frequently un- reliable, and it is necessary to supplement what little we do know with evidence from recent epidemics among Native Americans. For example, in 1952, an outbreak of measles among the Native American inhabitants of Ungava Bay, Quebec, affected 99 percent of the population and killed 7 percent, even though some had the benefit of modern medicine. Cases such as this demonstrate that even diseases that are not normally fatal can have destroying consequences when they strike an immunologically defenseless community.
单选题 According to the passage, virgin-soil epidemics can be distinguished from other catastrophic out- breaks of diseases in that virgin-soil epidemics______.
【正确答案】 C
【答案解析】事实细节题。文章第二段第一句中。这句话其实是对virgin-soil epidemics 的一个定义，在定义中肯定要提到它与其他类似事物不同的方面，[C]项是原文的同义转述，原文中的关键词是had no previous contact with。[A]与[B]项在原文中都没有提到；[D]认为它不如其他疾病那样对医学治疗反应敏感，但文中并未提到这一点。
单选题 Which of the following can be inferred from the text concerning Spanish tribute records?
【正确答案】 D
【答案解析】推理判断题。到原文第二段中间指出，reports of horrible epidemics and steep population de- clines，…of Spanish tribute records and other sources，[D]为此意的同义转述。选项[A]是从the surviving re- cords of North America 得出的结论，而不是Spanish tribute records。[B]项的内容与原文意思相反; [C]项所叙述的 certain diseases were unknown in the pre-Columbian New World 没有错误，但是这不是Spanish tribute records 所记录的内容，而是early chronicles of America 中所提到的。
单选题 It can be inferred from the text about the Native American inhabitants of Ungava Bay that they
【正确答案】 A
【答案解析】推理判断题。答案在原文的最后一段的第二句至末尾。选[B]的同学读懂了最后一段的内容，而且[A]项的内容确实是在最后一段中提到过，但并不是通过推断得出的；选项[C]过于绝对，没有注意到文中提到的这次疾病大流行只是记录中的一次，但并不能说明就是最后一次；选[D]认为“这种流行病在19世纪以前没发生过”，对某种流行病没有记录，并不说明这种病没有流行过，只是没有留下记录而已。
单选题 The author mentions the 1952 measles outbreak most probably in order to______.
【正确答案】 C
【答案解析】推理判断题。原文最后一段第一句中说这些关于流行病的记录很少，而且往往不可靠。后面举了一个例子，来证实上一段中提到的在殖民地时代所记录的流行病是可靠的。原文中在提到affected 99 per- cent of the population and killed 7 percent，even though some had the benefit of modern medicine 可以看出， modern medicine 并未对这次流行病产生很大的效果，所以，作者不太可能用这个不成功的事实来论述现代医药对流行病的效果，[A]不正确；[B]项的意思是倡导针对流行病问题的新方法，在原文中没有涉及；[D]选巧误会了作者的目的，作者并不仅仅是为了反驳针对殖民地美洲历史记录的不可靠性这种说法的，而是为了说明有些记录还是可靠的。
单选题 The author''s purpose in writing this passage is______.
【正确答案】 A
【答案解析】观点态度题。答案在原文第一段最后一句中可以得出。这句话阐述了一种观点，这同时也是作者的看法，在后面的段落中，作者给出了自己的依据，举了一些例子。[B]项的意思是调和相反的观点，但文中并未提到两种或几种相反的观点，调和也就无从谈起；[C]选项误把第一段最后一句的内容当作了一个misconception，所以认为作者要反驳这种误解；[D]项认为作者为了详细分析一个观点，而作者并未对这一观点进行分析，只是在各个段落中提出了较多的例子，并未加以分析。