2015英语二阅读真题同源过关练习连载

Chenjian
2014/10/09 08:08:09 B1
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@ jamie 不好意思，同学。这是补上来的答案。英语二阅读真题同源过关练习连载六答案：答案：ACBDDBeing a vegetarian is no easy task: The difficulty of maintaining a balanced diet is enough to drive an herbivore back to the land of hamburgers and chicken wings. And human vegetarians aren’t the only ones who have to get creative with their diet — giant pandas do the same. Until now, scientists have been uncertain how pandas fulfill their dietary needs through the consumption of only one, highly fibrous plant – bamboo. The new study answers this question: Pandas consume a mix of two bamboo species, as well as several parts of the plant, in order to meet their dietary needs.Giant pandas have only recently acquired their herbivorous lifestyles. 第一题答案出处Their bodies still have the small stomach and short gastrointestinal tracts of their carnivorous ancestors, and they still require the protein and nutrients from a meat-based diet. In a six-year study based on a panda reserve in China, researchers attached GPS collars to three male and three female pandas in order to observe what they ate within their natural habitat. The team then took samples of the animals’ various food sources in order to measure the nutritional makeup of the plants — specifically the amounts of nitrogen, phosphorous and calcium they contained. These three elements are the most essential aspects of a mammal’s diet.The researchers found that pandas maintain a complicated food choreography over the course of a year. In the spring, pandas switch from the leaves of one kind of bamboo, wood bamboo, to its shoots, which are rich in nitrogen and phosphorous. As the shoots mature — and consequently loose nutrients — the pandas migrate to higher elevations and eat the shoots of a different plant, arrow bamboo, which have copious amounts of both nutrients. They switch again by mid-July, this time to eat the leaves of the arrow bamboo, which are rich in calcium. By mid-August, females return to lower elevation to give birth and return to feeding on wood bamboo leaves. By repeating this pattern each year, pandas are able to maintain adequate levels of essential nutrients. Yet hardship and death are still common for the endangered species, with mortality peaking in March and April due to the low nutritional quality of winter leaves.第二题答案出处Understanding how pandas feed themselves in the wild is an important step in the conservation of the species. By knowing what they eat, scientists can consciously create a strategy to protect the animals, 第三题答案出处along with their current and future food sources. While being a vegetarian might be hard, pandas prove that a little creativity goes a long way. 第四题答案出处全文翻译：成为一名合格的素食者绝非易事：保持日常饮食的均衡性是一项高难度的任务，这常常使得素食主义者们前功尽弃，纷纷向汉堡包和鸡翅缴械投降。然而，人类素食者并非唯一面临饮食搭配挑战的生物——大熊猫们也经常受到此问题的困扰。大熊猫的唯一主食是富含纤维素的竹子，长期以来，科学家们都无法彻底弄清楚，只进食一种食物的大熊猫是如何满足自身营养需求的。而最近一项新研究为我们解开了疑惑：为了保证自身的需求，大熊猫会混合着进食不同的两种竹子，并且还会吃掉植物的一些其他部分。从进化史来看，大熊猫是最近才变为素食主义者的。至今，它们的体内依然保留着其肉食性祖先们那小型的胃和短小的肠道，并且它们仍旧需要食用肉类，以满足身体对蛋白质和营养的需求。研究人员在中国大熊猫保护区进行了为期六年的研究，为了观察野生大熊猫在自然栖息地的饮食情况，他们给三只雄性与三只雌性熊猫佩戴上了GPS项圈。随后，研究团队对熊猫所吃的各类食物来源进行了抽样，并分析了其中的营养成分——特别是氮、磷和钙的含量，这三种元素正是大熊猫饮食中最重要的成分。研究人员发现，熊猫的日常食谱并不单一，它们会随着一年四季的变化改变自己的食谱，在木竹、箭竹，竹叶和嫩芽之间进行选择。春季里，熊猫会选择食用木竹上富含磷和氮的新生嫩芽，而不是竹叶。然而，当这些嫩芽成熟了之后，其中的氮元素含量将持续减小，这时，熊猫将迁徙至海拔更高的地区，在那里进食另一种富含氮磷元素的竹子——箭竹。七月中旬时，熊猫会再次改变食谱，开始食用箭竹上富含钙元素的的竹叶。而当八月中旬，熊猫将返回低海拔的地区，重新将木竹的竹叶纳入主要食谱，并在那里繁衍后代。熊猫的食谱变化每年都会如此循环一次，这使得它们能够获得足够的关键营养元素。尽管如此，苦难和死亡仍然始终萦绕在这种濒危动物的头上，每到三、四月份，随着冬季长出的竹叶营养物质减少，熊猫种群的死亡率就会升至最高点。研究熊猫在野生环境中的饮食习惯，对于保护这种濒危物种非常重要。通过了解它们的饮食，科学家们能够根据熊猫们目前和未来的食物来源，制定出相应的保护策略。尽管当一名素食主义者并非易事，但熊猫们能够在这条路上坚持至今，确实有属于自己的一套创新方法。