按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
Paragraph 3~5
Dandelions are good examples of opportunists。 Their seedheads raised just high enough above the ground to catch the wind； the plants are no bigger than they need be； their stems are hollow； and all the rigidity comes from their water content。 Thus； a minimum investment has been made in the body that becomes a platform for seed dispersal。 These very short…lived plants reproduce prolifically； that is to say they provide a constant rain of seed in the neighborhood of parent plants。 A new plant will spring up wherever a seed falls on a suitable soil surface； but because they do not build big bodies； they cannot compete with other plants for space； water； or sunlight。 These plants are termed opportunists because they rely on their seeds’ falling into settings where competing plants have been removed by natural processes； such as along an eroding riverbank； on landslips； or where a tree falls and creates a gap in the forest canopy。
Opportunists must constantly invade new areas to compensate for being displaced by more competitive species。 Human landscapes of lawns； fields； or flowerbeds provide settings with bare soil and a lack of competitors that are perfect habitats for colonization by opportunists。 Hence； many of the strongly opportunistic plants are the common weeds of fields and gardens。
Because each individual is short…lived； the population of an opportunist species is likely to be adversely affected by drought； bad winters； or floods。 If their population is tracked through time； it will be seen to be particularly unstable — soaring and plummeting in irregular cycles。
文章的3~5段以蒲公英为例介绍了植物中的opportunist，以及这类植物的生长、繁殖、维持生命的特点。
文中画线部分即这类植物的特点：
1。 拥有较小的体态、生存时间很短，以便节省能量以供繁殖，并且不断以种子的形态进入新的生长地点；
2。 由于生存时间较短，因此自然灾害会对它们造成严重影响，导致其种群数量的变化极不稳定。
Paragraph 6
The opposite of an opportunist is a competitor。 These organisms tend to have big bodies； are long…lived； and spend relatively little effort each year on reproduction。 An oak tree is a good example of a competitor。 A massive oak claims its ground for 200 years or more； outcompeting all other would…be canopy trees by casting a dense shade and drawing up any free water in the soil。 The leaves of an oak tree taste foul because they are rich in tannins； a chemical that renders them distasteful or indigestible to many organisms。 The tannins are part of the defense mechanism that is essential to longevity。 Although oaks produce thousands of acorns； the investment in a crop of acorns is small compared with the energy spent on building leaves； trunk； and roots。 Once an oak tree becomes established； it is likely to survive minor cycles of drought and even fire。 A population of oaks is likely to be relatively stable through time； and its survival is likely to depend more on its ability to withstand the pressures of competition or predation than on its ability to take advantage of chance events。 It should be noted； however； that the pure opportunist or pure competitor is rare in nature； as most species fall between the extremes of a continuum； exhibiting a blend of some opportunistic and some competitive characteristics。
与opportunist相对应，本段以橡树为例，同样从“形态、生存时间、种群数量、能量分配”等方面介绍植物中的competitor的特点：
1。 具有强大的体态，能生存更长时间，不会将大部分能量用于繁殖；
2。 由于生存时间较长，且能抵抗恶劣环境，因此橡树的种群数量相对稳定。
二、阅读题目类型
托福阅读的题型主要分为以下几类：
Factual Information（事实信息题）
Negative Factual Information（否定排除题）
Inference（推论题）
Rhetorical Purpose（修辞题）
Vocabulary（词汇题）
Reference（指代题）
Sentence Simplification（句子简化题）
Insert Text（插入文字题）
Fill in a Table（图表题）
Prose Summary（总结题）
下面，我们将为考生提供一些解题的思路：
1。 查找信息类题目
这类问题主要考查考生对原文信息的理解，比如事实信息题（Factual Information）和否定排除题（Negative Factual Information）。这类题目要求选出与文中内容相符或不符的一项。这类问题的提问方式通常为：
According to the passage； 。。。
Based on the information in。。。
例如：
Reading Passage
Based on the information in paragraph 1； which of the following best explains the term wind farms？
Farms using windmills to pump water
Research centers exploring the uses of wind
Types of power plant common in North Dakota
Collections of wind turbines producing electric power
In 1994 there were nearly 20；000 wind turbines worldwide； most grouped in clusters called wind farms that collectively produced 3；000 megawatts of electricity。 Most were in Denmark （which got 3 percent of its electricity from wind turbines） and California （where 17；000 machines produced 1 percent of the state’s electricity； enough to meet the residential needs of a city as large as San Francisco）。 In principle； all the power needs of the United States could be provided by exploiting the wind potential of just three states — North Dakota； South Dakota； and Texas。
根据题干中的paragraph 1和wind farms这两个信息，我们可以快速定位到原文第一段的相应内容：In 1994 there were nearly 20；000 wind turbines worldwide； most grouped in clusters called wind farms that collectively produced 3；000 megawatts of electricity。 从这句话中可以得知wind turbines grouped in clusters 即是文中提问的wind farm，所以选第4项。
除了事实信息题和否定排除题以外，在做图表题时也需要利用查找定位的方法，回到原文中寻找答案。
2。 推论题
对于推论题（Inference）这类在文中没有直接表达的问题，可以根据文中陈述的已知信息推断出来。通常这类问题会以这样的形式提问：
What can be inferred from the passage？
比如下面的例子：
Reading Passage
What are the bones found in the Lascaux caves believed to indicate？
Wild animals sometimes lived in the cave chambers。
Artists painted pictures on both walls and bones。
Artists ground them into a fine powder to make paint。
Artists developed special techniques for painting the walls。
In Southwest France in the 1940’s； playing children discovered Lascaux Grotto； a series of narrow cave chambers that contain huge prehistoric paintings of animals。 Many of these beasts are as large as 16 feet （almost 5 meters）。 Some follow each other in solemn parades； but others swirl about； sideways and upside down。 The animals are bulls； wild horses； reindeer； bison； and mammoths outlined with charcoal and painted mostly in reds； yellow； and browns。 Scientific analysis reveals that the colors were derived from ocher and other iron oxides ground into a fine powder。 Methods of applying color varied： some colors were brushed or smeared on rock surfaces and others were blown or sprayed。 It is possible that tubes made from animal bones were used for spraying because hollow bones； some stained with pigment； have been found nearby。
这道题询问从洞穴中发现的骨头可以得到什么结论。根据关键词bones，可以定位到该段的末尾句。
根据tubes made from animal bones were used for spraying以及some stained with pigment，可以知道将空心的骨头当做绘画工具的方法。故选第4项。
3。 词汇及语言修辞类题目
托福阅读考试的修辞题（Rhetorical Purpose）、词汇题（Vocabulary）、指代题（Reference）、句子简化题（Sentence Simplification）和插入文字题（Insert Text）都是与文字和措辞有关的题目。这类题