单选题

Ants as a Barometer of Ecological Change

At picnics, ants are pests. But they have their uses. In industries such as mining, farming and forestry ,they can help gauge (测量) the health of the environment by just crawling around and being antsy.
It has been recognized for decades that ants—which are highly sensitive to ecological change—can provide a near-perfect barometer of the state of all ecosystem. Only certain species, for instance, will continue to thrive (兴旺, 欣欣向荣)at a forest site that has been cleared of trees. Others will die out for lack of food. And still others will move in and take up residence.
By looking at which species populate a deforested area, scientists can determine how "stressed" the land is. They do this by sorting the ants, counting their numbers and comparing the results with those of earlier surveys. Ants are used simply because they are so common and comprise so many species.
Where mine sites are being restored, for example, some ant species will recolonize the stripped land more quickly than others. This allowed scientists to gauge the pace and progress of the ecological recovery. Australian mining company Capricorn Coal Management has been successfully using ant surveys for years to determine the rate of recovery of land that it is replanting near its German Creek mine in Queensland.
Ant surveys also have been used with mine—site recovery projects in Africa and Brazil, where Warm climates encourage dense and diverse ant populations. "We found it worked extremely well there, "says Jonathan Majer, a professor of environmental biology. Yet the surveys are perfectly suited to climates throughout Asia, he says, because ants are so common throughout the region. As Majer puts it. "That's the great thing about ants. "
Ant surveys are so highly-regarded as ecological indicators that governments worldwide accept their results when assessing the environmental impact of mining and tree harvesting. Yet in other businesses, such as farming and property development, ant surveys aren't used widely. Why not? Because many companies can't afford the expense or the laboratory time needed to sift(细查, 祥查) results for a comprehensive survey. The cost stems, also, from the scarcity of ant species.

单选题 Ants are used to assess the state of an ecosystem for all the following reasons EXCEPT

【正确答案】 B

【答案解析】文章的第二、三段给出了科学家利用蚂蚁来评估一个地方生态系统的状况的原因。第二段第一句说：It has been recognized for decades that ants—which are highily sensitive to ecological change-can provide a near-perfect barometer of the state of an ecosystem(几十年来蚂蚁对生态变化极度敏感，一直被认为是一个生态系统状态的几近完美的晴雨表)，由此可见，对生态变化极度敏感是科学家选择蚂蚁的前提条件，即B选项的陈述是正确的。第二段最后一句说：Ants are used simply because they are so common and comprise so many species(人们选择使用蚂蚁只是因为它们的存在非常普遍，而且物种非常丰富)，也就是A和D选项所陈述的内容。只有B选项在文中找不到依据，因此成为了本题的正确答案。

单选题 What will happen at a forest site that has been cleared of trees according to the passage?

【正确答案】 C

【答案解析】根据题干定位到第二段：Only certain species, for instance, will continue to thrive at a forest site that has been cleared of trees. Others will die out for lack of food. And still others will move in and take up residence(例如，在树木被砍光的森林地带，只有有限的物种能够繁荣地生存下去，其他的物种会由于缺少食物而灭绝，还有一些其它物种会移居到这里定居下来)，与此陈述相符的只有C项，因此本题的正确答案为C。

单选题 Scientists can determine how seriously an area has been affected by deforestation by

【正确答案】 A

【答案解析】根据题干定位到第三段。第三段第一句指出：By looking at which species populate a deforested area. scientists can determine how "stressed" the land is(通过调查哪些动物种类生活在一个树木被伐光的地区，科学家们可以确定这个地区生态的破坏程度)，A选项与此相符，故为正确答案。在接来的内容中作者介绍了科学家通常选择蚂蚁作为调查的对象，并给出了具体的原因和做法，B和C选项都是具体的步骤，单独的一种行为并不能完成整个的调查，因此排除。而D项与原文内容不符，并没有说分析以往数据，而是说把此次数据与以往数据作对比，故排除。

单选题 Ants surveys are perfectly suited to climates in

单选题 According to the passage, in some businesses ant surveys are not used very widely because

【正确答案】 A

【答案解析】根据题干定位到最后一段第四句：Because many companies cacan't afford the expense or the laboratory time needed to sift results for a comprehensive survey(因为很多公司付不起相关的费用，或等不起为一项复杂的调查验证结果的时间)，显然A选项与此句相符，因此为正确答案。虽然说需要的时间长，但并没有指明具体的时间，因此排除D。最后一段第一句指出，世界上所有的国家都接受蚂蚁调查的结果，由此排除B选项。前面第三段最后一句就已经说明科学家选择蚂蚁的原因之一是因为它们的分布非常普遍，由此排除C选项。