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之四

4、Directions:

You are going to read a list of headings and a text about preparing in the academiccommunity. Choose the most suitable heading from the list A-F for each numbered paragraph (41-45). The first and last paragraphs of the text are not numbered. There is one extra heading which you do not need to use. Mark your answers on ANSWER SHEET 1. (10 points)

Until about two million years ago Africa's vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation-i.e., one approximating the ideal of a vegetational climax. (41). Early attempts at mapping and classifying Africa's vegetation stressed this relationship: sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.

(42). In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects: the general scale of treatment to be adopted, and the degree to which human modification is to be comprehended or discounted.

(43). Quite the opposite assumption is now frequently advanced. An intimate combination of many species-in complex associations and related to localized soils, slopes, and drainage-has been detailed in many studies of the African tropics. In a few square miles there may be a visible succession from swamp with papyrus, the grass of which the ancient Egyptians made paper and from which the word "paper" originated, through swampy grassland and broad-leaved woodland and grass to a patch of forest on richer hillside soil, and finally to juicy fleshy plants on a nearly naked rock summit.

(44). Correspondingly, classifications have differed greatly in their principles for naming, grouping, and describing formations: some have chosen terms such as forest, woodland, thorn-bush, thicket, and shrub for much of the same broad tracts that others have grouped as wooded savanna (treeless grassy plain) and steppe (grassy plain with few trees). This is best seen in the nomenclature, naming of plants, adopted by two of the most comprehensive and authoritative maps of Africa's vegetation that have been published: R. W. J. Keay's Vegetation Map of Africa South of the Tropic of Cancer and its more widely based successor, The Vegetation Map of Africa, compiled by Frank White. In the Keay map the terms "savanna" and "steppe" were adopted as precisedefinition of formations, based on the herb layer and the coverage of woody vegetation; the White map, however, discarded these two categories as specificclassifications. Yet any rapid absence of savanna as in its popular and more general sense is doubtful.

(45). However, some 100 specific types of vegetation identified on the source map have been compressed into 14 broader classifications.

[A] As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic potential.

[B] In regions of higher rainfall, such as eastern Africa, savanna vegetation is maintained by periodic fires. Consuming dry grass at the end of the rainy season, the fires burn back the forest vegetation, check the invasion of trees and shrubs, and stimulate new grass growth.

[C] Once, as with the scientific treatment of African soils, a much greater uniformity was attributed to the vegetation than would have been generally accepted in the same period for treatments of the lands of western Europe or the United States.

[D] The vegetational map of Africa and general vegetation groupings used here follow the White map and its extensive annotations.

[E] African vegetation zones are closely linked to climatic zones, with the same zones occurring both north and south of the equator in broadly similar patterns. As with climatic zones, differences in the amount and seasonal distribution of precipitation constitute the most important influence on the development of vegetation.

[F] Nevertheless, in broad terms, climate remains the dominant control over vegetation. Zonal belts of precipitation, reflection latitude and contrasting exposure to the Atlantic and Indian oceans and their currents, give some reality to related belts of vegetation.

[G] The span of human occupation in Africa is believed to exceed that of any other continent. All the resultant activities have tended, on balance, to reduce tree cover and increase grassland; but there has been considerable dispute among scholars concerning the natural versus human-caused development of most African grasslands at the regional level.

答案

41.F 42.A 43.C 44.G 45.D

总体分析

本文是一篇介绍非洲植被研究的科普性文章。

第一段:在非洲植被的图形绘制及其分类中很早就重视了植被与气候之间的密切关系。

第二段:随着人们对非洲植物的了解增加,对植物的命名、分类和绘制图形变得更加具体,许多有关植物区域的规划也被提出来。

第三段:现在人们更强调非洲植物的多样性而非一致性。

第四段:学者们对非洲草地发展的原因,对植物群系的命名、归类以及描述的原则都存在分歧。

第五段:介绍现在非洲植被图谱对植物的归类法。

[A] 随着人们对植物了解的增加,对植物的命名、分类和绘制图形也更加具体。

[B] 在高降水量的地区,大草原的植被因周期性的火灾而得以保存。

[C] 非洲东部植被被认为有很大的一致性。

[D] 现在的植物图谱及植物分类都受怀特图谱的影响。

[E] 影响植被发展的几个因素。

[F] 叙述了影响植被的气候因素。

[G] 学者们对于导致非洲草地发展的原因,存在很大的分歧。

试题精解

41.[精解] 本题考查的知识点是:段落内一致性原则+上下文的衔接

本题空格出现在第一段中,应起到承上启下的作用。上文提到了影响非洲植被的多种因素,并强调人类活动对植被气候的影响。空格下文提到早期对非洲植被的研究重视植物带与气候的关系。可见,该段主要围绕"气候"与"非洲植被"展开论述。预测空格处的内容应和段落主题保持一致。[E]出现了关键词"climatic"和"vegetation",但它主要论述的是"气候带",而非"气候"。[F]出现了关键词"climate"和"vegetation"。其中however一词表明与上文构成转折关系,从"强调人类活动的影响"转向"强调气候的影响"。[F]最后出现的belts of vegetation与空格下文plant zones是同义表达,相互呼应。

42.[精解] 本题考查的知识点是:内容的衔接

本题空格出现在第二段开始。下文的特征词in addition表明空格部分与下文存在递进关系。下文指出,当人们发现了更多不同的植物区域时,许多规划接连被提出。[A]中"随着人们对植物了解的增加(more has become known of ...)"与下文中"人们发现更多形状和大小不一的植物区域(more ... have been recognized)"内容很接近,出现了衔接。从[A]提到的"植物命名、分类和绘制图形的具体化"到下文"治理植物区域的规划的提出"也存在着递进关系。

43.[精解] 本题考查的知识点是:内容的衔接

本题空格出现在第三段开始。下文的第一句话指出,现在,人们常常提出完全相反的假设。由此可知,空格处论述的内容应与下文相反。从第三段末句"在很小的面积里都可能出现多种植被类型"的论述可知,下文应主要论述物种的多样性。与此能够形成对照的是[C],它强调了植被的一致性(uniformity)。

44.[精解] 本题考查的知识点是:内容的衔接

本题空格出现在第四段开始。下文特征词correspondingly(相应地)表明空格部分与下文存在因果关系。此外,下文中出现了some和others两个代词,指代不明确,需要通过空格处的内容将其具体化。下文首先指出,有关植物群系的命名、归类以及描述原则是大相径庭的。接着以学者对地带的不同命名为例予以说明。因此下文主要论述的是学者在植物研究中存在的分歧。[G]论述的正是这方面的内容,它指出学者们对导致非洲草地发展的原因存在分歧。[G]中的grasslands与下文的savanna和steppe呼应,下文some和others都指的是[G]中的scholars。具有干扰性的是[A],它出现了与下文相同的字眼"naming"、"classification"、"mapping"等,但它论述的是"非洲植物种类",而且最后出现的是"可能出现的气候",这些都无法与下文构成很好的衔接。因此[G]为正确项。

45.[精解] 本题考查的知识点是:上下文的衔接+词语的呼应

本题空格出现在第五段开始。下文however一词表明空格部分与下文构成转折关系。下文提到,源图中100种植物具体类别被简化为14种涵盖更广的类别。由此可知,空格部分应出现与"图"或"植物类别"有关的内容。符合要求的是[D],其中the White map与第四段提到的Frank White呼应,its extensive annotations与下文100 specific types呼应。

核心词汇或超纲词汇

(1)vegetation(n.)(统称)植物;(尤指某地或环境的)植被,植物群落,草木

(2)current(n.)(海洋或江河的)水流,潮流,气流;电流;思潮,潮流

(3)mapping(n.)(地图等)图形的绘制

(4)discount(v.)认为不重要,不重视,不全信;打折出售

(5)localized(a.)在小范围内的,局部的,如a ~ infection局部感染

(6)on balance权衡起来,两相比较,如~ I think we should benefit by adopting the scheme.(权衡起来,我们采用这个方案应该会受益。)

(7)formation(n.)组成物,形成物,如massive rock ~s块状岩层

(8)nomenclature(n.)(尤指某学科的)命名法

全文翻译

直到大约200万年以前,非洲的植被总是被这些因素所影响:气候的交互作用,地质、土壤和地下水的条件,以及动物的活动。然而,人类活动的出现扩大了动物活动的影响,并不断使充分发展的"自然"植被--即,近似理想的植被气候--的构想变得不现实。但是,广义上说,气候仍然是影响植被的主要因素。区域性的降水带、纬度的反射以及暴露于截然不同的大西洋和印度洋气流之下,使相应的植被带的出现成为可能。有关非洲植被的图形绘制及其分类的早期努力就十分重视这种相关性:有时植物带的名称直接源于气候。这里讨论的"带"的概念仅限于广义和描述性的含义。

当人们对非洲好几万植物种类以及其复杂的生态了解得更多时,植物的命名、分类和绘制图形也变得更加具体,开始强调实际存在的而不是推测可能出现的气候。此外,随着时间的推移,人们发现了更多形状和大小不一的植物区域。因此,许多规划一个接一个地被提出,它们都涉及两个重要方面的观点:将要采取的治理手段的一般范围以及人类的影响将要被理解或忽视的程度。

曾经,在对非洲土地的科学治理中,其植被的一致性被认为比同时期如果在西欧或美国进行土地治理所能普遍接受的更大。现在,人们常常提出完全相反的假设。在许多有关非洲热带地区的研究中,多个物种的密切结合--复杂的相互联系以及与局部的土壤、坡度和排水条件的关系--已经被详细地给予了说明。在几平方英里内,就可以看得见植被的更替性:从长有纸草的沼泽(纸草是古埃及人用来做纸的草,"纸"这个词就来源于它),穿过沼泽草地、阔叶树林和草到在肥沃的山腰土上长着的一片树林,最后到几乎光秃秃的岩石山顶上生长的肉质多汁的植物。

人类在非洲活动的时间被认为比在其它任何洲都要长。总的来说,所有活动的结果都倾向于减少森林覆盖面积和增加草地面积。但是在地区层面上,关于是自然还是人为导致了大多数非洲草地的发展,学者们存在很大的分歧。相应地,这些学者在他们命名、归类以及描述植物群系的原则上也是大相径庭。对于几乎同样宽广的地带,一些学者将其归类为非洲大草原(没有树木)和西伯利亚大草原(树木稀疏),而另一些学者则选用如森林、林地、荆棘、灌木丛、灌木这样的术语来描述。这种差异性在已出版的两幅有关非洲植被最全面最权威的图谱所采用的植物术语中可见一斑。这两幅图是:R. W. J•凯伊编写的《北回归线以南的非洲植被图》和后来出版的资料来源更为广泛的由富兰克•怀特编辑的《非洲植被图》。以木本植群的覆盖率和草本层为依据,凯伊的图采用"非洲大草原"和"西伯利亚大草原"对植物群系进行精确定义;而在怀特的图中,却并不采用这两种具体的分类方法。然而,普遍而广泛意义上的非洲大草原的迅速缺失却是令人质疑的。

现在使用的非洲植被图谱及普通的植被归类法都沿用怀特的图谱及其广博的注解。但是,源图中确认的100种植物的具体类别被简化为14种涵盖更广的类别。

干扰项

[B] 在高降水量地区,比如非洲东部,大草原的植被因周期性的火灾而得以保存。雨季末的大火燃烧了干草,火烧退了森林植被,阻碍了树木和灌木的滋生,并促进了新草的生长。

[E] 非洲植被带与气候带有着紧密的联系,赤道以南和赤道以北出现了结构非常相似的植被带。气候带、降雨量和降雨的季节性分布的差异一起对植被发展构成了最重要的影响。
关键字:考研英语
生词表:
  • academic [,ækə´demik] 移动到这儿单词发声 a.学术的 n.大学学生 四级词汇
  • vegetation [,vedʒi´teiʃən] 移动到这儿单词发声 n.植物;生长 四级词汇
  • increasingly [in´kri:siŋli] 移动到这儿单词发声 ad.日益,愈加 四级词汇
  • arisen [ə´rizn] 移动到这儿单词发声 arise的过去分词 四级词汇
  • modification [,mɔdifi´keiʃən] 移动到这儿单词发声 n.变更;修正;缓和 四级词汇
  • wooded [´wudid] 移动到这儿单词发声 a.多树林的 四级词汇
  • grassy [´grɑ:si] 移动到这儿单词发声 a.多草的;青草味的 四级词汇
  • authoritative [ɔ:´θɔrətətiv] 移动到这儿单词发声 a.可信的;命令的 四级词汇
  • tropic [´trɔpik] 移动到这儿单词发声 n.热带地区;回归线 四级词汇
  • precise [pri´sais] 移动到这儿单词发声 a.精确的;清楚的 四级词汇
  • definition [,defi´niʃən] 移动到这儿单词发声 n.限定;定义;明确 四级词汇
  • compressed [kəm´prest] 移动到这儿单词发声 a.压缩的 六级词汇
  • uniformity [,ju:ni´fɔ:miti] 移动到这儿单词发声 n.同样;一致(性) 六级词汇
  • equator [i´kweitə] 移动到这儿单词发声 n.赤道 四级词汇
  • broadly [´brɔ:dli] 移动到这儿单词发声 ad.广,宽;明白;粗鲁 六级词汇
  • dominant [´dɔminənt] 移动到这儿单词发声 a.统治的;占优势的 四级词汇


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