例2：定位词为非原文原词的情况

Paragraph 2: Playappears to be a developmental characteristic of animals with fairlysophisticated nervous systems, mainly birds and mammals. Play has been studiedmost extensively in primates and canids (dogs). Exactly why animals play isstill a matter debated in the research literature, and the reasons may not bethe same for every species that plays. Determining the functions of play is difficultbecause the functions may be long-term, with beneficial effects not showing upuntil the animal's adulthood. (TPO30 Role of Play in Development)

According toparagraph 2, which of the following presents a particular challenge toresearchers who study play behavior in animals?

O The delay between activities and the benefitsthe animal derives from them.

O The difficulty in determining which animalspecies play and which do not.

O The fact that for most animals, there is noclear transition from youth to full adulthood.

O The lack of research on the play behavior ofanimals other than canids and primates.

分析：此题干中的定位词为challenge & researchers, 在原文中考生们无法找到这两个定位词，但是可以找到challenge的同义替换形式difficult, 因此该句即是我们所需要的定位句。

问题2：定位词在原文中出现不止一次。

Paragraph 7: Occasionally, a sequence offossil-rich layers of rock permits a comprehensive look at one type of organismover a long period of time. For example, Peter Sheldon' s studies of trilobites, a now extinct marineanimal with a segmented body, offer a detailed glimpse into three million yearsof evolution in one marine environment. In that study, each of eight different trilobitespecies was observed to undergo a gradual change in the number of segments ---typically an increase of one or two segments over the whole time interval. Nosignificant discontinuous were observed, leading Sheldon to conclude thatenvironmental conditions were quite stable during the period he examined. (TPO30 The Pace of Evolutionary Change)

According toparagraph 7, Peter Sheldon’s studies demonstrated which of the following abouttrilobites?

O They underwent gradual change over a longtime period

O They experienced a number of discontinuoustransitions during their history

O They remained unchanged during a long periodof environmental stability

O They evolved in ways that cannot be countedfor by either of the two competing theories.

分析：通过题干找出定位词Peter Sheldon & trilobites, 然后回读原文进行定位，考生们会发现这两组定位词在原文中分别出现2次。因此，考生们需要定位的范围变大，难度由此也加大了。这种类型的事实信息题是考生们在考场上最不愿意看到的一种，但是很不幸的是由最新的几套TPO中的例题显示这种类型的题目正在变多，所以朗阁海外考试研究中心的专家请各位考生平时在练习时加大这种类型的考题的练习。

Step3: 比较定位句与选项的内容，选出语义最接近的选项。

注意：1). 考生们所看到的定位句可能是一个非常长的句子，而选项相对比较简短，所以考生们一定要学会从长难句中截取你所需要的能回答问题的部分。简单点说就是比如题干中问你why….;那么，此时考生们在分析原文定位句时应该重点看because这种能够解释的部分。

2). 考生们在比较定位句与选项时切忌不能随意推理，只需要把握文本的字面意思即可。

例1：

Paragraph 3: To what extent competition determines the composition of acommunity and the density of particular species has been the source ofconsiderable controversy. The problem is that competition ordinarily cannot beobserved directly but must be inferred from the spread or increase of onespecies and the concurrent reduction or disappearance of another species. TheRussian biologist G. F. Gause performed numerous two-species experimentsin the laboratory, in which one of the species became extinct when only asingle kind of resource was available. On the basis of these experiments and offield observations, the so-called law of competitive exclusion was formulated,according to which no two species can occupy the same niche. Numerousseeming exceptions to this law have since been found, but they can usually beexplained as cases in which the two species, even though competing for a majorjoint resource, did not really occupy exactly the same niche. (TPO 29 Competition)

Paragraph 3 supports the idea that Gause’s experiments were importantbecause they

O provided a situation in whichcompetition could be removed from the interaction between two species

O showed that previous ideasabout the extent to which competition determines the composition of a communitywere completely mistaken

O helped establish thatcompetition will remove all but one species from any given ecological niche

O offered evidence thatcompetition between species is minimal when there is an overabundance of asingle food source

解题步骤：

1). 读题干，找出定位词Gause’s experiments, 然后把握题目问的内容是有关于G的实验的importance。

2). 通过定位词回到原文进行定位，位于第三句话。但是第三句只提到了定位词之一，接下来的第四句中提到了由此形成了一个law, 可以对应题干中想问的importance。

3). 第3句和第4句两句定位句的大意为“当只有一种食物来源被提供时，两种物种中的一种会消亡。参照这些实验和观察就形成了竞争互斥规律----没有哪两种物种可以占据同样的生态圈”，接下来浏览四个选项，发现C选项大意吻合----确定了竞争将会移除其他所有的物种在任何一个生态圈里面。

例2：

As railroad linesfanned out from Chicago, farmers began to acquire open prairie land in Illinois andthen Iowa, putting the fertile, deep black soil into production. Commercialagriculture transformed this remarkable treeless environment. To settlersaccustomed to eastern woodlands, the thousands of square miles of tall grasswere an awesome sight. Indian grass, Canada wild rye, and native big bluestemall grew higher than a person. Because eastern plows could not penetrate thedensely tangled roots of prairie grass, the earliest settlers erected farmsalong the boundary separating the forest from the prairie. In 1837, however,John Deere patented a sharp-cutting steel plow that sliced through the sodwithout soil sticking to the blade. Cyrus McCormick refined a mechanical reaperthat harvested fourteen times more wheat with the same amount of labor. By the1850s McCormick was selling 1,000 reapers a year and could not keep up withdemand, while Deere turned out 10,000 plows annually. (TPO 33 Railroads andCommercial Agriculture in Nineteenth-Century United States)

Accordingto paragraph 5, the firstsettlersgenerally did not farm open prairie land because

A.they could not plow it effectively with the tools that were available.

B.prairie land was usually very expensive to buy.

C.the soil along boundaries between the forest and the prairie was more fertile thanthe soil of the open prairie.

D.the railroad lines had not yet reached the open prairie when the first settlersarrived.

解题步骤：

1).读题干，找出定位词settlers& open prairie land, 并且抓住题干问的重点是because

2).根据定位词定位到第一句和第三句这样的语义群，这样的语义群可以给我们提供一个大范围定位，然后接下来考生们在第四句里看到了because,所以第四句就是我们需要的精确定位点。

3).定位句的语义大约为“因为东部的耕种工具无法穿透这里的根部缠结在一起的草，因此，早期的定居者们将农场建立在了远离草原的边界地区。”接下来浏览四个选项，只有A选项提到了因为耕作工具的原因，所以选择A选项。

3. 总结：

1).此种题型必须要先阅读题干，摸清题干所问的具体内容，然后再读文章进行定位

2).此种题型既可以只考察某一个特定的定位句理解;同时也可以考察2-3个定位句范围的意群理解。但无论怎样，考生绝对不是漫无目的地搜索，而是根据题干有目的性地寻找答案。