A
In the 1950s, Central American commercial banana growers were facing the death of their most economical product, the Gros Michel banana. Now it’s happening again to its successor—the Cavendish.
With its easily transported, thick-skinned and sweet-tasting fruit, the Gros Michel banana plant dominated the plantations of Central America. United Fruit, the main grower and exporter in South America at the time, mass-produced its bananas in the most efficient way possible: it cloned shoots from the stems of plants instead of growing plants from seeds, and cultivated them in densely packed fields.
Unfortunately, these conditions are also perfect for the spread of the fungus(真菌), which attacks the plant’s roots and prevents it from transporting water to the stem and leaves. The TR-1 strain of the fungus was resistant to crop sprays and travelled around on boots or the tyres of trucks, slowly infecting plantations across the region. In an attempt to escape the fungus, farmers abandoned infected fields, flooded them and then replanted crops somewhere else, often cutting down rainforest to do so.
Their efforts failed. So they searched for a variety of bananas that the fungus didn’t affect. They found the Cavendish, which wasn’t as well suited to shipping as the Gros Michel, but its bananas tasted good enough to keep consumers happy. Most importantly, TR-1 didn’t seem to affect it. In a few years, United Fruit had saved itself from bankruptcy by filling its plantations with thousands of the new plants. However, the Cavendish banana itself is far from safe. In 2015, the exports of Cavendish bananas had dropped by 46 per cent thanks to a combination of another strain of the fungus, TR-4, and bad weather.
Racing against the inevitable, scientists are working on solving the problem by genetically modifying the Cavendish with genes from TR-4-resistant banana species. Researchers have successfully grown two kinds of modified plants which have remained resistant for three years so far. But some experts think this is just a complicated version of the same temporary solution the original Cavendish provided. If the new bananas are planted in the same monoculture(单种栽培) as the Cavendish and the Gros Michel, the risk is that another strain of the disease may rise up to threaten the modified plants too.
【文章大意】本文主要讲了香蕉种植者不断提高香蕉抵御病毒的能力, 然后作者提到了转基因香蕉。
1. Mass-produced bananas are .
A. grown from seeds because it’s efficient
B. cloned because it’s fast and cheap to grow them
C. sweeter than other bananas
D. exported to Central America
【解析】选B。细节理解题。根据第二段的United Fruit, the main grower and exporter in South America at the time. . . it cloned shoots from the stems of plants instead of growing plants from seeds, and cultivated them in densely packed fields. 可知该大规模生产的香蕉是农民克隆而成的。所以选B。
2. The spread of the TR-1 strain was .
A. caused by lack of water
B. sped up by the flooding of banana fields
C. slowed down by crop spraying
D. helped by the movement of people and vehicles
【解析】选D。细节理解题。根据第三段的. . . and travelled around on boots or the tyres of trucks, slowly infecting plantations across the region. 可知这种病毒可以通过待在卡车的行李箱或轮胎上进行传播。所以选D。
3. Genetically modified bananas may .
A. mean farmers can grow the Gros Michel again
B. cause farmers to repeat the mistakes of the past
C. encourage farmers to try new growing methods
D. only be a short-term solution
【解析】选D。推理判断题。根据最后一段的. . . is just a complicated version of the same temporary solution the original Cavendish provided. 可知, 这仅仅是一个临时的解决方案。
4. How would you describe the writer’s opinion about the future of the Cavendish?
A. Optimistic. B. Pessimistic.
C. Cautious. D. Uninterested.
【解析】选C。推理判断题。根据最后一段的If the new bananas are planted in the same monoculture. . . the risk is that another strain of the disease may rise up to threaten the modified plants too. 可知, 作者对 the Cavendish的未来还是有点担忧, 希望能谨慎行事。故作者对香蕉转基因的态度是小心谨慎的, 所以选C。
【知识拓展】长难句分析
United Fruit, the main grower and exporter in South America at the time, mass-produced its bananas in the most efficient way possible: it cloned shoots from the stems of plants instead of growing plants from seeds, and cultivated them in densely packed fields.
分析: 句子主语是United Fruit。the main grower and exporter in South America at the time是United Fruit的同位语。谓语是mass-produced。宾语是its bananas。in the most efficient way possible作状语。冒号后面对way作了具体的解释说明。
翻译: United Fruit, 那时南美主要的种植者和出口者, 以最有效的方法大规模生产香蕉: 它从植物的茎上克隆幼苗, 而不是用种子育苗, 然后在密集的田地里种植它们。
