托福阅读TPO31第1篇:Speciation in Geographically Isolated Populations

Evolutionary biologists believe that speciation,the formation of a new species, often begins whensome kind of physical barrier arises and divides apopulation of a single species into separatesubpopulations. Physical separation between subpopulations promotes the formation of newspecies because once the members of one subpopulation can no longer mate with members ofanother subpopulation, they cannot exchange variant genes that arise in one of thesubpopulations. In the absences of gene flow between the subpopulations, genetic differencesbetween the groups begin to accumulate. Eventually the subpopulations become sogenetically distinct that they cannot interbreed even if the physical barriers between themwere removed. At this point the subpopulations have evolved into distinct species. This routeto speciation is known as allopatry (“alio-” means “different”，and “patria” means “homeland”).

进化生物学家认为物种形成(也就是新物种的产生)经常是某种物理障碍(地理隔离)的出现把一个单一物种群分为隔离的亚种群。亚种群的身体隔离促进了新物种的产生，因为一旦亚种群中的成员无法与其他亚种群中的成员交配，那么亚种群之间就没有变种基因的交换。缺乏了基因交流，亚种群之间的遗传差异就开始变大。最终这些亚种群的基因差异变得十分明显，以至于它们无法进行种族内的交配，即使它们之间的物理障碍已经消除。这时，这些亚种族就演化成了独立的物种。这样的物种形成的方式被称作异域性(“alio-”意思是“不同的”,“patria”意为“故乡”)。

Allopatric speciation may be the main speciation route. This should not be surprising,since allopatry is pretty common. In general, the subpopulations of most species areseparated from each other by some measurable distance. So even under normal situationsthe gene flow among the subpopulations is more of an intermittent trickle than a steadystream. In addition, barriers can rapidly arise and shut off the trickle. For example, in the1800s a monstrous earthquake changed the course of the Mississippi River, a large riverflowing in the central part of the United States of America. The change separated populationsof insects now living along opposite shore, completely cutting off gene flow between them.

异域性物种形成可能是最主要的物种形成方式。这没什么惊讶的，因为异域现象太常见。一般而言，大多数的物种的亚种族都是被遥远距离所隔开，所以即使在正常条件下，这些亚物种间的基因流动倒更像是一条断断续续的细流，而不是一条不停流淌的小溪。并且，障碍也会迅速出现来截断这条细流。例如，19世纪的一次大地震改变了密西西比河(美国中部的一条大河)的流向，这个变化使得当地的昆虫分离开来，它们现在居住于河的两岸，彼此的基因流动已被完全截断。

Geographic isolation also can proceed slowly, over great spans of time. We find evidenceof such extended events in the fossil record, which affords glimpses into the breakup offormerly continuous environments. For example, during past ice ages, glaciers advanceddown through North America and Europe and gradually cut off parts of populations from oneanother. When the glacier retreated, the separated populations of plants and animals cameinto contact again. Some groups that had descended from the same parent population wereno longer reproductively compatible—they had evolved into separate species. In othergroups, however, genetic divergences had not proceeded so far, and the descendants could stillinterbreed—for them, reproductive isolation was not completed, and so speciation had notoccurred.

地理隔离也能缓慢地进行，会跨越很长的时间段。我们在化石记录中找到了这种长期证据，从中我们可以瞥见先前延续环境的破碎。比如说，在过去的冰河世纪，经过北美和欧洲的冰川最终把种群的部分彼此切断，当冰川消退后，这些分离的动植物种群又会连到一起。一些起源于同一母群的群体变得不再那么容易兼容——它们演化成了分开的物种。然而，在另一些群体里，遗传差异并没有那么明显，后代们还是可以种族内互相交配的繁殖，隔离并没有彻底，所以物种形成就没有发生。

Allopatric speciation can also be brought by the imperceptibly slow but colossalmovements of the tectonic plates that make up Earth’s surface. About 5 million years ago suchgeologic movements created the land bridge between North America and South America thatwe call the Isthmus of Panama. The formation of the isthmus had important consequences forglobal patterns of ocean water flow. While previously the gap between the continents hadallowed a free flow of water, now the isthmus presented a barrier that divided the AtlanticOcean from the Pacific Ocean. This division set the stage for allopatric speciation amongpopulations of fishes and other marine species.

异域性物种的形成也可能是由构成地球表面的地壳构造板块运动所产生的，这个运动虽略微缓慢但却异常剧烈。大约五百万年前这种地质运动形成了连接北美和南美的大陆桥，也就是我们今天所说的巴拿马地峡。巴拿马地峡的形成对全球洋流的模式产生了重大的影响。之前，大陆间的这个缺口可以让水自由流动，而现在巴拿马地峡在大西洋和太平洋之间形成了一道屏障。这个地域分割为鱼和其他海洋物种的异域性物种形成创造了条件。

In the 1980s, John Graves studied two populations of closely related fishes, onepopulation from the Atlantic side of isthmus, the other from the Pacific side. He comparedfour enzymes found in the muscles of each population. Graves found that all four Pacificenzymes function better at lower temperatures than the four Atlantic versions of the sameenzymes. This is significant because Pacific seawater is typically 2 to 3 degrees cooler thanseawater on the Atlantic side of isthmus. Analysis by gel electrophoresis revealed slightdifferences in amino acid sequence of the enzymes of two of the four pairs. This is significantbecause the amino acid sequence of an enzyme is determined by genes.

20世纪80年代，约翰??格雷夫斯研究了两个紧密相关的鱼种，一种来自地峡的大西洋一侧，另一种来自太平洋那一侧。他比较了每个鱼种肌肉里的四种酶。格雷夫斯发现在低温条件下，位于太平洋一侧的鱼种里的全部四类酶比大西洋一侧的四种酶功能更好。这个发现很重要，因为太平洋的海水的水温通常要比地峡另一侧大西洋的海水低2到3度。凝胶电泳的分析显示，四对中的两对酶的氨基酸序列略有不同。这也很重要，因为酶的氨基酸序列是由基因决定的。

Graves drew two conclusions from these observations. First, at least some of the observeddifferences between the enzymes of the Atlantic and Pacific fish populations were not randombut were the result of evolutionary adaption. Second, it appears that closely relatedpopulations of fishes on both sides of the isthmus are starting to genetically diverge fromeach other. Because Graves’s study of geographically isolated populations of isthmus fishesoffers a glimpse of the beginning of a process of gradual accumulation of mutations that areneutral or adaptive, divergences here might be evidence of allopatric speciation in process.

根据这些观测，格雷夫斯得出了两个结论。，在这些观测到的大西洋和太平洋鱼种体内酶的差异中，至少有一些不是偶然的，它们是适应进化的结果。第二，似乎地峡两侧原 本密切相关的鱼种开始有了基因分化。因为格雷夫斯关于地峡鱼类地域隔离的种群研究为中性或适应性突变的逐渐累积过程的开始提供了一些线索。这里的差异可能会给正在进行的异域性物种的形成提供证据。

托福阅读试题

1.The word "promotes" in the passage isclosest in meaning to

A.describes.

B.encourages.

C.delays.

D.requires.

1.promote本身是促进的意思。另外原文这个句子意思是subpopulations间的物理分割...了新物种的形成，A描 述，B促使，C减弱，D要求。 所以B最合适的。

 

2.According to paragraph 1, allopatric speciation involves which of the following?

A.The division of a population into subspecies.

B.The reuniting of separated populations after they have become distinct species.

C.The movement of a population to a new homeland.

D.The absence of gene flow between subpopulations.

2.根据allopatric进行定位，可定位至本段的最后一句。最后一句是对前面现象的一个命名和定义。也就是说前 面的内容，就是allopatry的意 思。A与原文不附，原文说的 是物理 barrier 把 population 分割成 subpopulation，B 也不对， 对应Eventually这句。C原文没提到。D正确，对应从In the absence开始到最后。

 

3.Why does the author provide the information that "the subpopulations of mostspecies are separated from each other by some measurable distance"?

A.To indicate how scientists are able to determine whether subpopulations of a species areallopatric.

B.To define what it means for a group of animals or plants to be a subpopulation.

C.To suggest that allopatric speciation is not the only route to subpopulation.

D.To help explain why allopatric speciation is a common way for new species to come about.

3.高亮句前面的一句话，也就是本段的句(主旨句)，allopatry是main speciation route。本段都是围绕着这个主题来进行的。所以选择D。

 

4.The word "accumulate" in the passage is closest in meaning to

A.Become more significant.

B.Occur randomly.

C.Gradually increase in number.

D.Cause changes.

4.词汇所在句说群落间基因的区别开始accumulate。 Eventually对理解这个词很有 帮助，也就是说是渐渐发展的，才能说最终。所以答案在A，C之间。但因为这里强调了缓慢的过 程，gradually更合适。

 

5.In paragraph 2,why does the author mention that some insect populations wereseparated from each other by a change in the course of Mississippi River caused by anearthquake?

A.To make the point that some kind of physical barrier separates the subpopulations of mostspecies.

B.To support the claim that the condition of allopatry can sometimes arise in a short time.

C.To provide an example of a situation in which gene flow among the subpopulations of aspecies happens at a slow rate.

D.To explain why insects living along opposite shores of the Mississippi River are very differentfrom each other.

5.For example后面就是题目中的内容，那么也就是说作者用此作为例子来支持前 面的观点。而前面的观点是 barriers也有可能突然发生，然后截断了这种trickle。所以对应的是B。

 

6.According to paragraph 3，separation of subpopulations by glaciers resulted inspeciation in those groups of plants and animals that

A.were reproductively isolated even after the glaciers disappeared.

B.had adjusted to the old conditions caused by the glaciers.

C.were able to survive being separated from their parent population.

D.had experienced some genetic divergences from their parent population.

6.根据Glaciers 和 plants and animals定位，可得知这是glacier separation 导致的结果。所以对应选项A。

 

7.The word "colossal" in the passage is closet in meaning to

A.consistent.

B.gradual.

C.enormous.

D.effective.

7.Colossal本身是巨大的， 非常的意思，这里对应C选项。分析原文也可以得到正确答案，与colossal并列的词汇是slow，中间的逻辑关系词 是but,证明两者有转折关系。再经过推断，缓慢的过程但量 大的话就足以发生巨大的改变。所以选C。

 

8.According to paragraph 4, which of the following is true of the geologic movementsthat brought about the Isthmus of Panama?

A.The movements brought populations of certain fishes and marine organisms into contactwith one another for the first time.

B.The movements transferred populations of fishes and other marine animals between thePacific and Atlantic Oceans.

C.The movements created conditions that allowed water to flow more freely between the Pacificand Atlantic Oceans.

D.The movements created conditions for the formation of new species of fishes and othermarine animals.

8.根据 Isthmus of Panama 定位。从About开始。本段的 最后一句说了isthmus of Panama带来的结果，对应了D选项。

 

9.The word "sequence" in the passage is closet in meaning to

A.quality.

B.order.

C.function.

D.number.

9.高亮词所在句提到了氨基酸，酶，pairs这些话题，其实就是在说成对的基因，胶体电泳分析揭示了少量的氨基酸的不同。A质量，C 功能，D数量都不对，应该选择B顺序。

 

10.According to paragraph 5, by comparing the enzymes from two related groups offishes on opposite sides of the isthmus, Graves found evidence that

A.there were slight genetic divergences between the two groups.

B.the Atlantic group of fishes were descended from the Pacific group of fishes.

C.the temperature of water on either side of the isthmus had changed.

D.genetic changes in the Atlantic group of fishes were more rapid and frequent than in thePacific group of fishes.

10.跟上面一题对应的位置是一样的。或者可以根据Graves found定位，阅读后面的部分可得出答案A。

 

11.It can be inferred from paragraph 5 and 6 that the reason Graves concluded thatsome of the differences between the Pacific and Atlantic enzymes were not randomwas that

A.each of the Pacific enzymes works better in cooler waters.

B.the Enzymes of the Atlantic fish populations had not changed since the formation of theIsthmus of Panama.

C.gel electrophoresis showed that the changes benefited both the Atlantic and the Pacific fishpopulations.

D.the differences between the enzymes disappeared when the two fish populations wereexperimentally switched to other side of the isthmus.

11.A对应了标注句子，B明显错误，文章一直在说改变。C文章提到 gel electrophoresis的地方只是说氨基酸的顺序改变，但没说both benefited。D文章也没提到。

 

12.Which of the sentence below best expresses the essential information in thehighlighted sentence in the passage? Incorrect choices change the meaning inimportant ways or leave out essential information.

A.Graves's study provides evidence that isthmus fishes are in the process of becominggeographically isolated.

B.Graves's study of mutating isthmus fishes yields results that differ from results of otherstudies involving allopatric speciation.

C.Graves's study of isolated populations of isthmus fishes provides some evidence thatallopatric speciation might be beginning

D.Grave's study indicates that when isolated, populations of isthmus fished register neutralor adaptive mutations.

12.原文高亮句翻译为：格雷夫斯关于地峡鱼类地域隔离的种群研究为中性或适应性突变的逐渐累积过程的开始提供了一些线索，这里的差异可能会给正在进行的异域性物种的形成提供证据。所以主干部分为...的研究为..的开始提供了线索，对应C。

 

13. Look at the four squares [■] that indicate where the following sentence can beadded to the passage.Where would the sentence best fit? The formation of theisthmus had important consequences for global patterns of ocean water flow.

Allopatric speciation can also be brought by the imperceptibly slow but colossal movements ofthe tectonic plates that make up Earth's surface. ■【A】 About 5 million years ago suchgeologic movements created the land bridge between North America and South America thatwe call the Isthmus of Panama. The formation of the isthmus had important consequences forglobal patterns of ocean water flow. ■【B】 While previously the gap between the continentshad allowed a free flow of water, now the isthmus presented a barrier that divided the AtlanticOcean from the Pacific Ocean. ■【C】This division set the stage for allopatric speciation amongpopulations of fishes and other marine species. ■【D】

13.要插入的句子提到了 formation of the isthmus，那么证明句子前面的内容中己经出现了isthmus，而后面则是 要说明consequences。第二个空符合逻辑，所以选择B。

 

14. Directions: An introductory sentence for a brief summary of the passage isprovided below. Complete the summary by selecting the THREE answer choices thatexpress the most important ideas in the passage. Some sentences do not belong inthe summary because they express ideas that are not presented in the passages or areminor ideas in the passage. This question is worth 2 points.

Allopatric speciation takes place when physically separated populations of a single speciesgradually diverge genetically to the point of becoming unable to interbreed

A.Allopatric speciation is common because the gene flow between subpopulations is generallylimited and the barriers that completely separate subpopulations can arise in a variety ofways.

B.During past ice ages, some, but not all, subpopulations separated by glaciers evolved intodistinct species.

C.Speciation does not need to take place through allopatry because subpopulations will formdistinct species whenever there are adaptive advantages or not

D.Physical barriers from glaciers and the movement of tectonic plates form so slowly that thesubpopulations on either side of the barriers usually do not form distinct species.

E.Graves's study of fish populations separated by the Isthmus of Panama may well provide apicture of the beginning stages of speciation.

F.Graves's study of physically separated fish populations show that there must be largedifferences between the environments of the isolated populations if allopatric speciation is totake place.

14.ABE

托福阅读TPO31第2篇:Early Children Education

Preschools—educational programs for children under the age of five—differ significantly from one country to another according to the views that different societies hold regarding the purpose of early childhood education. For instance, in a cross-country comparison of preschools in China, Japan, and the United States, researchers found that parents in the three countries view the purpose of preschools very differently. Whereas parents in China tend to see preschools primarily as a way of giving children a good start academically, Japanese parents view them primarily as a way of giving children the opportunity to be members of a group. In the United States, in comparison, parents regard the primary purpose of preschools as making children more independent and self-reliant, although obtaining a good academic start and having group experience are also important.

由于不同社会持有的关于儿童早教目的观点的不同，学前班(5岁以下儿童的教育项目)的形式在不同国家也大不相同。比如说，在一项中、日、美三国的跨国学前班调査中，调査者发现这三个国家的父母对学前教育的看法大相径庭。中国的父母大都认为上学前班可以帮孩子们打开学术上的大门，日本父母则把其看做是一个使孩子融入集体的好机会。相比之下，美国父母认为学前班最主要的目的是让孩子减少依赖性并变得更加自立，尽管获得一个良好的学业开端和团队经验同样重要。

While many programs designed for preschoolers focus primarily on social and emotional factors, some are geared mainly toward promoting cognitive gains and preparing preschoolers for the formal instruction they will experience when they start kindergarten. In the United Stated, the best-known program designed to promote future academic success is Head Start. Established in the 1960s when the United States declared the War on Poverty, the program has served over 13 million children and their families. The program, which stresses parental involvement, was designed to serve the “whole child”, including children’s physical health, self-confidence, social responsibility, and social and emotional development.

许多为学龄前儿童设计的课程项目主要集中在社会因素和情感因素上，而有些主要是为提升学龄前孩子们的认知能力和给他们提供开始上幼儿园后会经历的正规指导。在美国，众所周知，为促进未来学术成功设计的项目叫“Head Start”，在20世纪60年代美国开始“对贫穷开战”时建立的。这个项目已经为超过13000000孩子和其家庭提供服务。其强调的是家长的参与，为培养“全方位发展的儿童”所设计的，包括孩子的身体健康、自信心、社会责任感以及社交能力与情感的发展。

Whether Head Start is seen as successful or not depends on the lens through which one is looking. If, for instance, the program is expected to provide long-term increases in IQ (intelligence quotient) scores, it is a disappointment. Although graduates of Head Start programs tend to show immediate IQ gains, these increases do lot last. On the other hand, it is clear that Head Start is meeting its goal of getting preschoolers ready for school. Preschoolers who participate in Head Start are better prepared for future schooling than those who do not. Furthermore, graduates of Head Start programs have better future school grade. Finally, some research suggests that ultimately Head Start graduates show higher academic performance at the end of high school, although the gains are modest.

“Head Start”的成功与否取决于人们看待的角度。比如说，如果人们希望它可以带来智商的长期増长，那它终将是令人失望。因为，尽管“Head Start”可以使智力迅速地提高，但这种増长并不会持续太久。另一方面，很显然，“Head Start”的目标是让学龄前儿童做好上学的准备。相对那些没参与过“Head Start”计划的孩子们而言，参加了这个项目的孩子们对学业有着更充分的准备。而且，“Head Start”的毕业生今后的学习成绩会更好。最后，调査表明，虽然收获一般，但最终“Head Start”的毕业生在高中结束时会取得更高的学术成就。

In addition, results from other types of preschool readiness programs indicate that those who participate and graduate are less like to repeat grades, and they are more like to complete school than readiness program, for every dollar spent on the program, taxpayers saved seven dollars by the time the graduated reached the age of 27.

此外，从其他类型的学龄前预备项目的结果来看，那些参加过学前项目的毕业生很少重读，他们更愿意完成学校而不是预备项目。在毕业生长到27岁时，纳税人在这个项目上曾经花费的每1美元都可省下7美元。

The most recent comprehensive evaluation of early intervention programs suggests that, taken as a group, preschool programs can provide significant benefits, and that government funds invested early in life may ultimately lead to a reduction in future costs. For instance, compared with children who did not participate in early intervention programs, participants in various programs showed gains in emotional or cognitive development, better educational outcomes, increased economic self-sufficiency, reduced levels of criminal activity, and improved health-related behaviors. Of course, not every program produced all these benefits, and not every child benefited to the same extent. Furthermore, some researchers argue that less-expensive programs are just as good as relatively expensive ones, such as Head Start. Still, the results of the evaluation were promising, suggesting that the potential benefits of early intervention can be substantial.

最近关于早期介入项目的综合评估表明，总的来说，学前项目可以带来巨大的收益，政府在早期投入的资金最终会减少未来的花销。比如说，与没有参与早期介入项目的孩子相比, 参加了各种项目的孩子在情感和认知能力上得到了提高，改善了教育成果，提高了经济的自足性，减少了犯罪行为的发生，健康行为得到了改进。当然，不是所有的项目都能产生这样的收益，也不是每个孩子都能得到同等程度的提高。此外，一些调査者称那些相对便宜的项目和昂贵项目结果一样好。评估的结果仍然很乐观，它认为早期介入的潜在好处是不可估量的。

Not everyone agrees that programs that seek to enhance academic skills during the preschool years are a good thing. In fact, according to developmental psychologist David Elkind, United States society tends to push children so rapidly that they begin to feel stress and pressure at a young age. Elkind argues that academic success is largely dependent upon factors out of parents’ control, such as inherited abilities and a child’s rate of maturation. Consequently, children of a particular age cannot be expected to master educational material without taking into account their current level of cognitive development. In short, children require development appropriate educational practice, which is education that is based on both typical development and the unique characteristics of a given child.

并不是所有人都认为在学前期追求学术上的提高是一件好事。事实上，据发展心理学家 大卫??艾尔凯德所说，美国社会急于催促逼迫孩子，以至于他们年纪小却感到压力。艾尔凯德认为学术上的成功主要取决于父母控制以外的因素，如天生的能力和孩子的成熟程度。因此，如果不考虑特定年龄段孩子们目前的认知发展水平，就不能期待他们掌握教材。总之，孩子们需要发展适当的教育实践，那就是基于孩子的典型发展和独特性的教育。

托福阅读试题

1.According to paragraph l, parents in Japantend to think of preschool primarily as a placewhere children can

A.get a good academic start.

B.expand their emotional development.

C.become more independent.

D.experience being part of a group.

1.根据题目中Parents in Japan，定位可直接得到答案D。

 

2.The word "Whereas" in the passage is closet in meaning to

A.Although.

B.Because.

C.Moreover.

D.Already.

2.这里对比了Chinese和Japanese家长之间的差别，所以A最合适。

 

3.The word "focus" in the passage is closet in meaning to

A.consider.

B.respect.

C.concentrate.

D.advise.

3.focus是集中的意思， 另外这里和focus配合的介词是on，concentrate也用 on，所以这里帮助推断。

 

4.It can be inferred from paragraph 2 that the Head Start program was designed toserve children who

A.come from families that do not have a lot of money.

B.are not doing very well in kindergarten.

C.were born in the 1950s.

D.need programs that focus primarily on social and emotional factors.

4.根据Head Start定位， 后面的内容就是对Head Start这个program的介绍，首先是 I960年开始的，和C矛盾， 然后说是在US宣布了 War on Poverty (贫穷)的时候，所以是为穷人设计的，符合A。 B没提到，D在这段的开头提到了，但是不是针对Head Start的描述，Head Start目标 是"whole child"，德智体美劳全面发展。

 

5.According to paragraph 3, the Head Start program had NOT been successful atwhich of the following?

A.Helping children adjust to school.

B.Providing long-term increase in IQ scores.

C.Improving school performance throughout high school.

D.Preventing children from being placed in special-education classes.

5.只有B不对应，其他的几个选项根据后文中的内容都是正确的。

 

6.In paragraph 4，the author mentions the "results from other types of readinessprograms" to

A.provide support for the idea that preschool readiness programs have been somewhatsuccessful.

B.question the idea that Head Start is more effective than other preschool readiness programs.

C.indicate school completion is usually the most reliable indicator of success in mostreadiness programs.

D.emphasize that participation in readiness programs can be increased if costs are reduced.

6.利用 results of readiness programs定位到本段句，本句内容：参加这些 program留级的可能性小，而且还能省钱，所以选A。

 

7.According to paragraph 4, a cost-benefit analysis of one preschool readinessprogram revealed that

A.only one dollar's worth of benefit was gained for every seven dollars spent on the program.

B.the benefits of the program lasted only until the participants reached age 27.C.taxpayerssaved seven dollars for every dollars spent on the program.

D.to be successful, the program would need to receive about seven times as much money as itcurrently receives.

7.A改变了原文意思，B文章没说只到27, D和原文意思正好相反。

 

8.The word "comprehensive" in the passage is closest in meaning to

A.easily understood.

B.thorough.

C.respectable.

D.objective.

8.comprehensive是全面的，综合的意思，使用代入法，A最易懂的，B完整的，C值得尊敬的，D客观的 中，AC可以排除，不通顺，B和D之间就需要理解 comprehensive的词意来确定。

 

9.Paragraph 5 mentions that participants in early intervention programs have beenshown to do all of the following better than nonparticipants EXCEPT

A.Take care of there health.

B.Support themselves financially.

C.Take care of their own children.

D.Have increased emotional development.

9.根据关键词定位至For instance开始的内容，其中不包括C。

 

10.According to paragraph 5, which of the following is true about the benefits ofearly intervention programs?

A.These programs produce good short-term benefits but few long-term benefits.

B.Only the most expensive programs provide substantial benefits.

C.The Head Start program provides a range of benefits that no other program can provide.

D.Some children benefit more than others do from these programs.

10.A对应 "reduction in future costs〃证明是 long term 的 benefit，所以A错误。B对应 "less-expensive programs are just as good as relatively expensive ones〃说明便宜和贵的一样好，B选项也不对。 C没提到。D对应not every child benefited to the same extent，正确。

 

11.The word "seek" in the passage is closet in meaning to

A.claim.

B.manage.

C.fail.

D.attempt.

11.seek本身是寻找，追求的意思。A是要求，B是设法，管理， C是失败，D是尝试，所以D 最合适。

 

12.The passage mentions "developmental psychologist David Elkind" in order to

A.give an example of an expert who has designed an effective early childhood educationprogram.

B.introduce an alternative view about the value of early childhood education.

C.explain why early childhood education programs are less effective in the United States thanin other countries.

D.refute the claim that academic success is dependent on factors outside parents' control.

12.关键词对应后，根据本段的句，Elkind是作为反面观点的例子出现的，所以是为了阐述另外一面的观点，选B。

 

13. Look at the four squares [■] that indicate where the following sentence can beadded to the passage.Where would the sentence best fit? According Elkind, not onlydoes this cause the child emotional distress, it also fails to bring the intendedcognitive gains.

Not everyone agrees that programs that seek to enhance academic skills during the preschoolyears are a good thing. ■【A】 In fact, according to developmental psychologist David Elkind,United States society tends to push children so rapidly that they begin to feel stress andpressure at a young age. ■【B】 Elkind argues that academic success is largely dependentupon factors out of parents'control, such as inherited abilities and a child's rate of maturation. ■【C】Consequently, children of a particular age cannot be expected to master educationalmaterial without taking into account their current level of cognitive development. ■【D】lnshort, children require development appropriate educational practice, which is education thatis based on both typical development and the unique characteristics of a given child.

13.要插入的句子中有not only，also的结构，那么起到的就是承上启下的作用。句子前面一定出现emotional distress的内容，后面要引出的就是 intended cognitive gains的相关内容，所以选B。

 

14. Directions: An introductory sentence for a brief summary of the passage isprovided below. Complete the summary by selecting the THREE answer choices thatexpress the most important ideas in the passage. Some sentences do not belong inthe summary because they express ideas that are not presented in the passages or areminor ideas in the passage. This question is worth 2 points.

Preschool programs provide opportunities for young children to develop socially,emotionally, and cognitively.

A.In addition to stressing academic development, preschools should be enjoyable, sincestudies show that children benefit from programs they find fun.

B.Preschool programs such as Head Start have been shown to help prepare children for schooland may also have long-team benefits in helping children become effective adults.

C.Studies have shown that preschool programs are most effective when they focus on only onearea of development rather than trying to serve the "whole child".

D.The primary purpose of preschool programs varies by country, with some stressing theimportance of group experience, and others self-reliance or getting a good academic start.

E.Critics of preschool programs argue that these programs put undue pressure on children andmay not be effective of children are not developmentally ready for academic work.

F.David Elkind is a critic of publicity funded preschool programs, arguing that the parentcannot control their children's emotional development.

14.BDE

托福阅读TPO31第3篇:Savanna Formation

Located in tropical area at low altitudes,savannas are stable ecosystems, some wet and somedry consisting of vast grasslands with scattered treeor shrubs. They occur on a wide range of soil typesand in extremes of climate. There is no simple or single factor that determines if a given sitewill be a savanna, but some factors seem to play important roles in their formation.

热带草原或热带稀树草原位于热带低海拔地区，干湿气候皆有。稀疏分布着树木和灌木的广阔大草原，其为一个稳定的生态系统。气候极端，涵盖了广泛的土壤种类。对于热带草原的形成原因，虽无单一的解释，但似乎仍有一些因素对其形成起到了重大作用。

Savannas typically experience a rather prolonged dry season. One theory behind savannaformation is that wet forest species are unable to withstand the dry season, and thussavanna, rather than rain forest, is favored on the site. Savannas experience an annual rainfallof between 1000 and 2000 millimeters, most of it falling in a five-to-eight month wet season.Though plenty of rain may fall on a savanna during the year, for at least part of the year littledoes, creating the drought stress ultimately favoring grasses. Such conditions prevailthroughout much of northern South America and Cuba, but many Central American savannasas well as coastal areas of Brazil and the island of Trinidad do not fit this pattern. In theseareas, rainfall per month exceeds that in the above definition, so other factors mustcontribute to savanna formation.

热带草原通常会经历十分漫长的旱季。热带草原形成理论之一，就是湿润的森木物种无法承受干燥的季节——这更有利于热带草原，而不是热带雨林的形成。热带草原的年降水量在1000到2000毫米，绝大多数降水都集中在长达5到8个月的雨季中。虽然每年的降水总量充足，但至少会有几个月几乎零降水，由此引起的干旱使得该地区最终只适合草地生长。这样的条件广泛地分布于南美北部和古巴的大部分地区，但也有例外，比如在中美洲的稀树大草原，巴西的沿海地区和特立尼达岛气候的类型就不一样。在这些地区每月的降水量超过了之前定义的降水量范围，因此还有其他因素影响着热带草原的形成。

In many characteristics, savanna soils are similar to those of some rain forests, thoughmore extreme. For example, savanna soils, like many rain forest soils, are typically oxisols(dominated by certain oxide minerals) and ultisols (soils containing no calcium carbonate),with a high acidity notably low concentrations of such minerals as phosphorus, calcium,magnesium, and potassium, while aluminum levels are high. Some savannas occur on wet,waterlogged soils; other dry, sandy, well-drained soils. This many seem contradictory, but itonly means that extreme soil conditions, either too wet or too dry for forests, are satisfactoryfor savannas. More moderate conditions support moist forests.

虽然极端，但在大多数特点上，热带草原和雨林的土壤还是相似的。比如说，和许多热带雨林土壤一样，热带草原的土壤通常为含酸量高的氧化土(某些氧化物矿物占主导)和老成土(这些土壤中不含碳酸钙，磷、钙、镁、钾这样的矿物质含量非常低，而铝的含量却很高)。有些热带草原的土壤潮湿，呈溃水状态;而有些的土壤却干燥、多沙、易排水。这看起来矛盾，但却意味着只有像过度湿润或过度干旱那样的极端土壤条件，才适合热带草原，温润的气候适合湿润的森林。

Waterlogged soils occur in areas that are flat or have poor drainage. These soils usuallycontain large amounts of clay and easily become water-saturated. Air cannot penetratebetween the soil particles, making the soil oxygen-poor. By contrast, dry soils are sandy andporous, their coarse textures permitting water to drain rapidly. Sandy soils are prone to theleaching of nutrients and minerals and so tend to be nutritionally poor. Though most savannasare found on sites with poor soils (because of either moisture conditions or nutrient levels ofboth), poor soils can and do support lush rain forest.

溃水土壤出现在地形平坦和排水性差的地方。这些土壤通常含有大量的黏土，这就会使它们很容易处于饱水状态。由于空气不能渗入土壤颗粒中，土壤的含氧量就低。与之相对，干燥土壤是多沙和多孔渗水的。它们的粗质结构可以让水很快排干。砂质土壤更易于营养物和矿物质的过滤渗漏，这就导致土壤缺乏营养。虽然大多数热带草原都位于贫瘠土壤区(无论是因为各自的水分条件还是营养等级)，但贫瘠土壤也的确能够长出繁茂的热带雨林。

Most savannas probably experience mild fires frequently and major burns every two yearsor so. Many savanna and dry-forest plant species are called pyrophytes, meaning they areadapted in various ways to withstand occasional burning. Frequent fire is a factor to whichrain forest species seem unable to adapt, although ancient charcoal remains from Amazonforest soils dating prior to the arrival of humans suggest that moist forests also occasionallyburn. Experiments suggest that if fire did not occur in savannas in the Americas, speciescomposition would change significantly. When burning occurs, it prevents competitionamong plant species from progressing to the point where some species exclude others,reducing the overall diversity of the ecosystem. But in experimental areas protected fromfire, a few perennial grass species eventually come to dominate, outcompeting all others.Evidence from other studies suggests that exclusion of fire results in markedly decreasedplant-species richness, often with an increase in tree density. There is generally little doubtthat fire is a significant factor in maintaining savanna, certainly in most regions.

大多数热带草原都可能经历着频繁的焚烧，而大约两年就有一次大火燃烧。许多热带草原和干燥林的植物种类被叫做耐火植物，意思是其善于用各种方法来抵御偶尔发生的燃烧。虽然追溯到人类初至时亚马逊森林土壤中遗留的古木碳表明湿润林带也会有不定期的燃烧，但频繁的大火还是热带雨林物种所不能适应的因素。实验表明，如果美国的热带草原没有发生大火，物种的构成就会变得完全不一样。焚烧的防止了植物之间的竞争，这就避免了因植物间的排挤而使整个生态系统的多样性发生变化。但是在防火实验区，一些多年生植物物种最终占得主导地位，胜过了其他物种。其他调査证据表明，没有焚烧则导致植物物种丰富性的显著减少，通常还会伴随着树的密度増加。这就可以确定，火是维持热带草原的重要因素。当然，这指的是在大多数地区。

【6】On certain sites, particularly in South America, savanna formation seems related tofrequent cutting and burning of moist forests for pastureland. Increase in pastureland andsubsequent overgrazing have resulted in an expansion of savanna. The thin upper layer ofhumus (decayed organic matter) is destroyed by cutting and burning. Humus is necessary forrapid decomposition of leaves by bacteria and fungi and for recycling by surface roots. Oncethe humus layer disappears, nutrients cannot be recycled and leach from the soil, convertingsoil from fertile to infertile and making it suitable only for savanna vegetation. Forests onwhite, sandy soil are most susceptible to permanent alteration.

在某些地区，特别是在南美洲，热带草原的形成可能和为了建造牧场而对湿润林地进行频繁的砍伐和焚烧有关。牧场的増加和随之而来的过度放牧导致了热带草原的扩张。稀薄的腐殖质(腐烂的有机物)上层被砍伐和焚烧行为所破坏。腐殖质是树叶被细菌和真菌迅速分解和根部表面循环的必需品。一旦腐面层消失了，营养物质便不能循环并渗入土壤中，土壤由肥沃变得贫瘠，这就使它只适合热带草原植被的生长。白土和砂土上的森林结构容易发生性的改变。

托福阅读试题

1.The word "prolonged" in the passage isclosest in meaning to

A.predictable.

B.destructive.

C.lengthy.

D.unproductive.

1.可以根据词根分析，原文中prolonged，词根为long，长度。Prolonged为延长的。选项中C，length本来是长度的意思，lengthy变为形容词格式，符合原词词义。

 

2.In paragraph 2，the author mentions savannas in Central America, Brazil, and theisland of Trinidad in order to

A.argue that these savannas are similar to those in South America and Cuba.

B.point out exceptions to the pattern of savanna formation in areas with drought stress.

C.provide additional examples of savannas in areas with five- to eight-month wet seasons.

D.indicate areas where savannas are being gradually replaced by rain forests.

2.以 savannas in Central America, Brazil, and theisland of Trinidad作为关键词定位到原文，看到这半句和前 半句中间有but的转折，那么也就是说centralAmerica，Brazil这些地方和前面介绍的不一样，所以是例外情况。

 

3.According to paragraph 3, rain forests and savannas differ in that

A.the soils in rain forests contain fewer minerals than savanna soils do.

B.savannas affect soil conditions more than rain forests do.

C.unlike rain forests, savannas prefer sandy, well-drained soils to soils that are very wet.

D.unlike rain forests, savannas may develop under both very dry and very wet soil conditions.

3.本段句就指出，rain forest和savannas的土壤是相似的，但是更极端一点。后面就给了examples。最后一句 给出了两种土壤的总结"this may seem….Either too wet or too dry for forests" 所以选 D。

 

4.The word "notably" in the passage is closest in meaning to

A.similarly.

B.especially.

C.usually.

D.relatively.

4.Notably从notice发展而来，以为显著的，因此选择B。另外也可通过and的并列格式来推断。

 

5.According to paragraph 3, all of the following are true of savanna soils EXCEPT

A.They have high concentrations of potassium.

B.They contain high levels of aluminum.

C.They are very acidic.

D.They contain large amounts of certain oxide minerals.

5.这一题对应for example后面的内容，A直接和红色标注部分矛盾，因此是要选的except的选项。

 

6.According to paragraph 4, which of the following is true of waterlogged soils?

A.Their upper layers are usually sandy and porous.

B.They cannot support savannas.

C.They contain little oxygen.

D.They are prone to the leaching of nutrients and minerals.

6.A对于"by contrast…"那一句，sandy soil和waterlogged soils 是相反的。B 与原文矛盾，上段最后就说要么很干要么很湿，waterlogged 就是很湿的那种。C对于那个 making the soil oxygen-poor。D对应"Sandy soils are prone to ....."，而不是选项中说的 waterlogged soils的特征。

 

7.The fact that "poor soils can and do support lush rain forest" suggests that

A.poor soils alone may not be enough to explain why an area becomes a savanna.

B.rain forest vegetation can significantly lower the quality of soils.

C.drought stress is the single most important factor in savanna formation.

D.minerals are more important than moisture for the growth of trees.

7.这句话说虽然几乎全部 的savannas都发生在poor soils之上，但是poor soils足以支撑茂盛的热带雨林。所以是转折，说明poor soils不是决定了savannas的因素， 还有别的。

 

8.Which of the sentences below best expresses the essential information in thehighlighted sentence in the passage? Incorrect choices change the meaning inimportant ways or leave out essential information.

A.Rain forest species seem unable to adapt to fires created by humans.

B.Ancient charcoal remains suggest that, prior to the arrival of humans, fires occurredfrequently in rain forests.

C.Ancient charcoal remains in Amazon forests suggest that rain forest species adapted to thearea long before the arrival of humans.

D.Rain forest species appear unable to adapt to frequent fires, but evidence from the pastsuggests that rain forests sometimes do burn.

8.原句主干是说frequent fire是造成热带雨林不能形成的原因，即使在人类出现之前亚马逊雨林也出现过偶尔的 燃烧。所以D是意思最完整的。可根据转折关系来判断。

 

9.The word "markedly" in the passage is closest in meaning to

A.dangerously.

B.noticeably.

C.rapidly.

D.gradually.

9.根据词根判断，原词词根为mark意为标注，跟选项中B的notice意思相近，所以选B。

 

10.Paragraph 5 supports which of the following statements regarding the importanceof fires in maintaining savannas?

A.Fires prevent the growth of pyrophytes.

B.Fires eliminate some species and thus reduce the overall diversity of the ecosystem.

C.Fires that occur once every two years are unlikely to help maintain savannas.

D.Fires prevent some species from eliminating other species with which they compete.

10.对应部分从but in experimental areas protected from fire开始，后面的内容都对其重要性进行了解释，如果没有火来保持savannas，那么就很少有perennial grass species可以outcompeting其他的种类，从而减少了plant-species的丰富，而树的密度则会更大。对应了 D的描述。

 

11.The word "subsequent" in the passage is closest in meaning to

A.expanded in area.

B.harmful.

C.following in time.

D.repeated.

11.subsequence是后果的意思，subsequent就是后来，然后的意思。因此选择C。

 

12.According to paragraph 6，human activity affects soils in all of the following waysEXCEPT

A.Decomposition of leaves occurs too fast for surface roots to obtain nutrients.

B.Nutrients are not recycled.

C.Humus is destroyed.

D.Certain soils become unable to support vegetation other than savanna vegetation.

12.human activity包括了cutting and burning，然后这句的后面，从''increase....''开始就是后果。先说humus is destroyed，对应 C，然后 humus 对于decomposition是非常必 要的，而 human activitydestroy了humus，所以减慢了decomposition，和A矛盾。 后面说 nutrients cannot被recycled，对应了B。converting那一句对应了D。

 

13. Look at the four squares [■] that indicate where the following sentence can beadded to the passage.Where would the sentence best fit? In addition, humans havecontributed to the conditions favoring the formation of savannas.

Most savannas probably experience mild fires frequently and major burns every two years or so.Many savanna and dry-forest plant species are called pyrophytes, meaning they are adapted invarious ways to withstand occasional burning. Frequent fire is a factor to which rain forestspecies seem unable to adapt, although ancient charcoal remains from Amazon forest soilsdating prior to the arrival of humans suggest that moist forests also occasionally burn.Experiments suggest that if fire did not occur in savannas in the Americas, speciescomposition would change significantly. When burning occurs, it prevents competitionamong plant species from progressing to the point where some species exclude others,reducing the overall diversity of the ecosystem. But in experimental areas protected fromfire, a few perennial grass species eventually come to dominate, outcompeting all others. ■【A】 Evidence from other studies suggests that exclusion of fire results in markedlydecreased plant-species richness, oftenwithan increase in tree density. ■【B】 There isgenerally little doubt that fire is a significant factor in maintaining savanna, certainly in mostregions.■【C】 On certain sites, particularly in South America, savanna formation seemsrelated to frequent cutting and burning of moist forests for pastureland. ■【D】 Increase inpastureland and subsequent overgrazing have resulted in an expansion of savanna. The thinupper layer of humus (decayed organic matter) is destroyed by cutting and burning. Humus isnecessary for rapid decomposition of leaves by bacteria and fungi and for recycling by surfaceroots. Once the humus layer disappears, nutrients cannot be recycled and leach from the soil,converting soil from fertile to infertile and making it suitable only for savanna vegetation.Forests on white, sandy soil are most susceptible to permanent alteration.

13.要插入的句子描述的是 savannas的形成原因，并且开头是in addition，证明是对前面句子的补充，前面句子说的应该是savannas形成的原因之一，对应了第二句。并且第三空后面的句子提到了cutting和burning，这些都是human activity。所以选 C。

 

14. Directions: An introductory sentence for a brief summary of the passage isprovided below. Complete the summary by selecting the THREE answer choices thatexpress the most important ideas in the passage. Some sentences do not belong inthe summary because they express ideas that are not presented in the passages or areminor ideas in the passage. This question is worth 2 points.

Several factors seem to play important roles in savanna formation.

A.Savannas can form in areas with a five- to eight-month wet season, but they more commonlyhave a

B.Soil stress caused by drought, extreme moisture, or low nutrient levels favors theformsticm of

C.Studies conducted in various regions indicate that an upper layer of white, sandy, soil is

D.Drought stress affects trees and shrubs in savannas far less than it affects savanna grasses.

E.Frequent fire is a major factor contributing to the formation and maintenance of

F.In some areas, human cutting and burning is associated with savanna formation, and

14.BEF

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