[外语类试卷]专业英语八级(阅读)练习试卷12及答案与解析.doc
《[外语类试卷]专业英语八级(阅读)练习试卷12及答案与解析.doc》由会员分享,可在线阅读,更多相关《[外语类试卷]专业英语八级(阅读)练习试卷12及答案与解析.doc(10页珍藏版)》请在麦多课文档分享上搜索。
1、专业英语八级(阅读)练习试卷 12及答案与解析 0 What makes for a successful invasion? Often, the answer is to have better weapons than the enemy. And, as it is with people, so it is with plants at least, that is the conclusion of a paper published in Biology Letters by Naomi Cappueeino, of Carleton University, and Thor A
2、rnason, of the University of Ottawa, both in Canada. The phenomenon of alien species popping up unexpected parts of the world has grown over the past few decades as people and goods become more mobile and plant seeds and animal larvae have hitched along for the ride. Most such aliens blend into the
3、ecosystem in which they arrive without too much fuss. (Indeed, many probably fail to establish themselves at all but those failures, of course, are never noticed.) Occasionally, though, something goes bananas and starts ttarts to take the place over, and an invasive species is born. Dr. Cappuceino a
4、nd Dr. Arnason asked themselves why. One hypothesis is that aliens leave their predators behind. Since the predators in their new homelands are not adapted to exploit them, they are able to reproduce unchecked. That is a nice idea, but it does not explain why only certain aliens become invasive. Dr.
5、 Cappuccino and Dr. Amason suspected this might be because native predators are sometimes “pre-adapted“ to the aliens defenees, but in other cases they are not. To test this, they had first to establish a reliable list of invaders. That is not as easy as it sounds. As they observe, “although there a
6、re many lists of invasive species published by governmental agencies, inclusion of a given species in the lists may not be entirely hee of political motivation“. Instead, they polled established researchers in the field of alien species, aski,g each to list ten invasive species and, for comparison,
7、ten aliens that just rubbed along quietly with their neighbours. The result was a list of 21 species widely agreed to be invasive and, for comparison, 18 non-invasive aliens. Having established these lists, they went to the library to find out what was known about the plants chemistry. Their aim was
8、 to find the most prominent chemical weapon in each plant, whether that weapon was directed against insects that might want to eat the plant, bacteria and fungi that might want to infect it, or other plants that might compete for space, water, nutrients and light. Botanists know a lot about which so
9、rts of compounds have what roles, so classifying constituent chemicals in this way was not too hard. The researchers then compared the chemical arsenals of their aliens with those of native North American plants, to see if superior (or, at least, unusual) weapomT was the explanation for the invaders
10、 success. Their hypothesis was that highly invasive species would have chemical weapons not found in native plants, and which pests, parasites and other plants would therefore not have evolved any resistance to. The more benign aliens, by contrast, were predicted to have arsenals also found in at le
11、ast some native species. And so it proved. More than 40% of the invasive species had a chemical unknown to native plants; just over 10% of the non-invasive aliens had such a chemical. Moreover, when they looked at past studies on alien plants that had examined how much such plants suffer from the de
12、predations of herbivorous insects, they found that the extent of the damage reported was significantly conelated with the number of native species with which that alien shared its principal chemical weapon. For alien plants, then, the real secret of success also as in human warfare is surprise. It i
13、s not that the chemicals concerned are more toxic in any general sense (indeed, successful invaders are often rare in their own native habitats). Rather, it is that the locals just dont see them coming. 1 In dozens of years, there are more cases of the invasion of alien species partly because ( A) p
14、lant seeds are resistant to antibiotics. ( B) people tend to hitch a ride. ( C) there are more circulation of goods. ( D) animal larvae become stronger. 2 The expression “something goes bananas“ in Paragraph 2 probably means something ( A) gets bananas. ( B) important happen. ( C) becomes crazy. ( D
15、) frightening happen. 3 The difference between Dr. Cappuccino and Dr. Arnasons hypothesis and the previous one is that ( A) the former mentions native predators of alien species. ( B) the former may account for the invasion of certain aliens. ( C) the latter explains the adaptation of the predators.
16、 ( D) the latter may explore the pre-adaptation of the predators. 4 Which of the following is TRUE of chemical weapons of invasive species? ( A) It is difficult to find the chemical weapons of invasive species. ( B) The most prominent chemical weapons of invaders explain their success. ( C) The less
17、 chemical weapons invaders have, the more benign they become. ( D) Most native plants dont have the same chemical weapons of aliens. 5 According to the text, the success of invasion lies in the fact that the native plants ( A) are unaware of the invasion of alien species. ( B) contain more poisonous
18、 chemicals. ( C) are defeated in plant warfare. ( D) may die out in their own habitats. 5 It is lunehtime at the Chateau de Bellerive, Prinee Sadruddin Aga Khans home on Lake Geneva. His guests are being served the elegant food associated with the princes kitchen. But the prince and his wife Catheri
19、ne are content to have a dish of brown rice and an accompanying salad. Can it be that they are not hungry., or is the price making a gesture: that aithough he is a rich man he has humble tastes? No one is so polite as to ask, but the guests may talk about it later. Sadruddin was disappointed that hi
20、s father did not name him as the next leader. But father apparently believed that his son lived only for pleasure. Sadruddins much publicized life with his first wife Nina, a model, may have made it seem so. “ Myths and labels become attached to people,“ he remarked later, “giving them a reputation
21、that does not always correspond to reality. “It could be that his father had mixed up Sadruddin with his half brother Aly, who was briefly married to Rita Hayworth, a Hollywood star, and was indeed a tearaway. In the event, when the Aga Khan died in 1957, the crown, and the title Aga Khan IV, went t
22、o Sadruddins nephew, the present holder. Sadruddin was then 24. At that age disappointments can usually be overcome, particularly if, like the prince, you have advantages. He had had an elitist education, at Le Rosay in Switzerland and Harvard. He spoke several languages, including French from his m
23、other, a Parisian, and Persian and English from his father. The amount of his persona fortune was unknown but it was certainly adequate. With these assets to sustain him, Sadruddin discovered what was to be his lifes work, to improve the lot of the worlds refugees. Like many people who came to do go
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
2000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 外语类 试卷 专业 英语 阅读 练习 12 答案 解析 DOC
