2. 考研
  3. In recent years a new farming revolution has begun, one that involves the【B1】______of life at a fundamental level—the gene. The

In recent years a new farming revolution has begun, one that involves the【B1】______of life at a fundamental level—the gene. The

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问题     In recent years a new farming revolution has begun, one that involves the【B1】______of life at a fundamental level—the gene. The study of genetics has 【B2】______ a new industry called biotechnology. As the name suggest, it【B3】______biology and modem technology through such techniques as genetic engineering. Some of the new biotech companies specialize in agriculture and are working feverishly to 【B4】______ seeds that give a high yield, that 【B5】______ diseases, drought and frost, and that reduce the need for 【B6】______ chemicals. If such goals could be achieved, it would be most【B7】______. But some have raised concerns about genetically engineered crops.
    In nature, genetic diversity is created within certain 【B8】______. A rose can be crossed with a different kind of rose, but a rose will never cross with a potato. Genetic engineering, 【B9】______ usually involves taking genes from one species and inserting them into another【B10】______to transfer a desired characteristic. This could mean, for example, selecting a gene which leads to the production of a chemical with anti-freeze 【B11】______ from an artic fish, and inserting it into a potato or strawberry to make it frost-resistant.【B12】______, then, biotechnology allows humans to【B13】______the genetic walls that separate species.
    Like the green revolution,【B14】______some call the gene revolution contributes to the problem of genetic uniformity—some say even more so【B15】______geneticists can employ techniques such as cloning and 【B16】______ culture, processes that produce perfectly【B17】______copies. Concerns about the erosion of biodiversity, therefore, remain. Genetically altered plants, however, raise new【B18】______,such as the effects that they may have on us and the environment. "We are flying blindly into a new【B19】______of agricultural biotechnology with high hopes, few constraints, and little idea of the potential【B20】______," said science writer Jeremy Rifkin.
【B8】
选项 A、lines
B、limits
C、space
D、ages
答案B
解析 考查名词辨析。本句在陈述基因多样性(genetic diversity)的特征，从后面一句的进一步解释(玫瑰可以与不同种类的玫瑰杂交，但绝不可以与土豆杂交)可知基因多样性的创立是有一定局限性的，B．limits“界限，限度”与within搭配，符合语境。其他三项均不符合此句语义。
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