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Passage Five The agricultural revolution in the nineteenth century involved two things the invention of labor-saving machinery and the development of scientific agriculture. Labor-saving machinery naturally appeared first where labor was scarce. "In Europe", said Thomas Jefferson," the object is to make the most of their land, labor being abundant; here it is to make the most of our labor, land being abundant." It was in America, therefore, that the great advances in nine-teenth-century agricultural machinery first came. At the opening of the century, with the exception of a crude plow, farmers could have carded practically all of the existing agricultural implements (家具) on their backs; by 1860, most of the machinery in use today had been designed in an early form. The most important of the early inventions was the iron plow. As early as 1790 Charles Newbold of New Jersey had been working on the idea of a cast-iron plow and spent his entire fortune in introducing his invention. The farmers, however, would have none of it, claiming that the iron poisoned the soil and made the weeds grow. Nevertheless, many people devoted their attention to the plow, until in 1869 James Oliver of South Bend, Indiana, turned out the first chilled-steel (冷淬钢) plow. What point is the author making by stating that farmers could carry nearly all their tools on their backs（）
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Passage Two Your mind like your body is a thing where the powers are developed by effort. This is a principal use, as I see it, of hard work in studies. Unless you train your body you can’t be a good sportsman, and unless you train your mind you can’t be much of a scholar. The four mi- les a boatman covers at top speed is in itself nothing to the good, but the physical capacity to hold out over the distance is thought to be of some value. So a good part of what you learn by hard study may not be retained forever, and may not seem to be of much final value, but your mind is a better and more powerful instrument because you have learned it. "Knowledge is power," but still more the ability of acquiring and using knowledge is power. If you have a trained and powerful mind, you are bound to have stored it with something, its value is more in what it can do, what it can grasp and use, than in what it contains; and if it were possible, as it is not, to come out of college with a trained mind and nothing useful in it, you would still be ahead, and still, in a manner, educated. The author emphasizes that many of the facts you acquire by hard study （）
Directions: There are five reading Passages in this part. Each passage is followed by five questions. For each question there are four suggested answers marked A, B, C and D. Choose one best answer and blacken the corresponding letter on ANSWER SHEET I.Passage OneSince the early 1980s, scientists have revealed some 40 human genes involved in cancer. These genes are essential for normal growth, but can be subverted to cause a tumor.Dr. Jorge Yunis of the University of Minnesota Medical School in Minneapolis has found that 70 percent of oncogenes, or cancer-causing genes, are located near inherited weak points on chromosomes(染色体). Varying from individual to individual, vulnerable to chemical carcinogens(致癌剂) ,X rays and other cancer-inducing agents."If a chromosome snaps apart in the immediate vicinity of an oncogene," says Yunis, "normal genetic control mechanisms could break down and the stage would be set for the formation of cancer." Younis hag shown that such a sequence occurs at the beginning of numerous leukemias (白血病), lymphomas (淋巴瘤) and some tumors of the lung, colon (结肠) and breast.Yunis and Other investigators have found that petroleum-based products--notably pesticides and insecticides--damage specific sites on at least two of the 23 pairs of human chromosomes that carry genetic information. Similarly, tobacco smoke tends to attack a part of another chromosome. According to the context, the word in "oncogenes" in para. 2 means （）
按照兼并的实现方式可以将兼并分为（）、（）和（）。
患者，男，50岁，蛋白尿5年，乏力、恶心2个月，平时血压偏高，贫血貌，血压180/110mmHg，心、肺听诊无异常发现，血肌酐113μmol/L，临床诊断尿毒症。 病人在降压、纠正酸中毒及降钾治疗中，突发四肢抽搐，但神志清楚，无二便失禁，最可能原因为( )
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