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  3. The Tough Grass That Sweetens Our Lives Sugar cane was once a wild grass that grew in New Guinea and was used by local peopl

The Tough Grass That Sweetens Our Lives Sugar cane was once a wild grass that grew in New Guinea and was used by local peopl

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问题                 The Tough Grass That Sweetens Our Lives
    Sugar cane was once a wild grass that grew in New Guinea and was used by local people for roofing their houses and fencing their gardens. Gradually a different variety evolved which contained sucrose(蔗糖)and was chewed on for its sweet taste. Over time, sugar cane became a highly valuable commercial plant, grown throughout the world.【B1】______
    Sugar became a vital ingredient in all kinds of things, from confectionery(糖果点心)to medicine, and, as the demand for sugar grew, the industry became larger de more profitable.【B2】______ Many crops withered(枯萎)and died, despite growers , attempts to save them and there were fears that the health of the plant would continues to deteriorate.
    In the 1960s, scientists working in Barbados looked for ways to make the commercial species stronger and more able to resist disease. They experimented with breeding programmes, mixing genes from the wild species of sugar cane, which tends to be tougher, with genes from the more delicate, commercial type.【B3】______This sugar cane is not yet ready to be sold commercially, but when this happens, it is expected to be incredibly profitable for the industry.
    【B4】______Brazil, which produces one quarter of the world’s sugar, has coordinated an international project under Professor Paulo Arrudo of the Universidade Estaudual de Campinas in Sao Paulo. Teams of experts have worked with him to discover more about which parts of the genetic structure of the plant are important for the production of sugar and its overall health.
    Despite all the research, however, we still do not fully understand how the genes in sugar cane. 【B5】______This gene is particularly exciting because it makes the plant resistant to rust, a disease which probably originated in India, but is now capable of infecting sugar cane across the world. Scientist believe they will eventually be able to grow a plant which cannot be destroyed by rust.
A. One major gene has been identified by Dr Angelique D’Hont and her team in Montpelier, France.
B. Since the 1960s, scientists have been analyzing the mysteries of the sugar cane’s genetic code.
C. Eventually, a commercial plant was developed which was 5 percent sweeter than before, but also much stronger and less likely to die from disease.
D. Sugar cane is now much more vigorous and the supply of suger is therefore more guaranteed.
E. Unfortunately, however, the plant started to become weaker and more prone to disease.
F. The majority of the world’s sugar now comes from this particular commercial species.
【B3】
选项
答案C
解析 句意：最终，一种商业作物被培育成了，这种作物比以前的品种还要甜5％，而且非常强壮，不容易病死。第三段前文提到，在20世纪60年代，科学家努力寻求改善这种经济作物的方法。他们把野外的甘蔗基因与商业品种的基因混合做繁育实验。可以推断下面应该介绍实验的结果，故选C。
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