上海新航道托福小編為托福考生們準備了托福閱讀TPO31原文,希望各位考生們在TPO真題里能夠得到鍛煉，祝廣大托福考生能夠取得理想成績。

  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”).

  進化生物學家認為物種形成(也就是新物種的產生)經常是某種物理障礙(地理隔離)的出現把一個單一物種群分為隔離的亞種群。亞種群的身體隔離促進了新物種的產生，因為一旦亞種群中的成員無法與其他亞種群中的成員交配，那么亞種群之間就沒有變種基因的交換。缺乏了基因交流，亞種群之間的遺傳差異就開始變大。最終這些亞種群的基因差異變得十分明顯，以至于它們無法進行種族內的交配，即使它們之間的物理障礙已經消除。這時，這些亞種族就演化成了獨立的物種。這樣的物種形成的方式被稱作異域性(“alio-”意思是“不同的”,“patria”意為“故鄉”)。

  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.

  異域性物種形成可能是最主要的物種形成方式。這沒什么驚訝的，因為異域現象太常見。一般而言，大多數的物種的亞種族都是被遙遠距離所隔開，所以即使在正常條件下，這些亞物種間的基因流動倒更像是一條斷斷續續的細流，而不是一條不停流淌的小溪。并且，障礙也會迅速出現來截斷這條細流。例如，19世紀的一次大地震改變了密西西比河(美國中部的一條大河)的流向，這個變化使得當地的昆蟲分離開來，它們現在居住于河的兩岸，彼此的基因流動已被完全截斷。

  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.

  地理隔離也能緩慢地進行，會跨越很長的時間段。我們在化石記錄中找到了這種長期證據，從中我們可以瞥見先前延續環境的破碎。比如說，在過去的冰河世紀，經過北美和歐洲的冰川最終把種群的部分彼此切斷，當冰川消退后，這些分離的動植物種群又會連到一起。一些起源于同一母群的群體變得不再那么容易兼容——它們演化成了分開的物種。然而，在另一些群體里，遺傳差異并沒有那么明顯，后代們還是可以種族內互相交配的繁殖，隔離并沒有徹底，所以物種形成就沒有發生。

  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.

  異域性物種的形成也可能是由構成地球表面的地殼構造板塊運動所產生的，這個運動雖略微緩慢但卻異常劇烈。大約五百萬年前這種地質運動形成了連接北美和南美的大陸橋，也就是我們今天所說的巴拿馬地峽。巴拿馬地峽的形成對全球洋流的模式產生了重大的影響。之前，大陸間的這個缺口可以讓水自由流動，而現在巴拿馬地峽在大西洋和太平洋之間形成了一道屏障。這個地域分割為魚和其他海洋物種的異域性物種形成創造了條件。

  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世紀80年代，約翰??格雷夫斯研究了兩個緊密相關的魚種，一種來自地峽的大西洋一側，另一種來自太平洋那一側。他比較了每個魚種肌肉里的四種酶。格雷夫斯發現在低溫條件下，位于太平洋一側的魚種里的全部四類酶比大西洋一側的四種酶功能更好。這個發現很重要，因為太平洋的海水的水溫通常要比地峽另一側大西洋的海水低2到3度。凝膠電泳的分析顯示，四對中的兩對酶的氨基酸序列略有不同。這也很重要，因為酶的氨基酸序列是由基因決定的。

  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.

  根據這些觀測，格雷夫斯得出了兩個結論。第一，在這些觀測到的大西洋和太平洋魚種體內酶的差異中，至少有一些不是偶然的，它們是適應進化的結果。第二，似乎地峽兩側原 本密切相關的魚種開始有了基因分化。因為格雷夫斯關于地峽魚類地域隔離的種群研究為中性或適應性突變的逐漸累積過程的開始提供了一些線索。這里的差異可能會給正在進行的異域性物種的形成提供證據。

  托福閱讀試題

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

  A.describes.

  B.encourages.

  C.delays.

  D.requires.

  1.promote本身是促進的意思。另外原文這個句子意思是subpopulations間的物理分割...了新物種的形成，A描 述，B促使，C減弱，D要求。 所以B最合適的。

  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.根據allopatric進行定位，可定位至本段的最后一句。最后一句是對前面現象的一個命名和定義。也就是說前 面的內容，就是allopatry的意 思。A與原文不附，原文說的 是物理 barrier 把 population 分割成 subpopulation，B 也不對， 對應Eventually這句。C原文沒提到。D正確，對應從In the absence開始到最后。

  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.高亮句前面的一句話，也就是本段的第一句(主旨句)，allopatry是main speciation route。本段都是圍繞著這個主題來進行的。所以選擇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.詞匯所在句說群落間基因的區別開始accumulate。 Eventually對理解這個詞很有 幫助，也就是說是漸漸發展的，才能說最終。所以答案在A，C之間。但因為這里強調了緩慢的過 程，gradually更合適。

  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后面就是題目中的內容，那么也就是說作者用此作為例子來支持前 面的觀點。而前面的觀點是 barriers也有可能突然發生，然后截斷了這種trickle。所以對應的是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.根據Glaciers 和 plants and animals定位，可得知這是glacier separation 導致的結果。所以對應選項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，這里對應C選項。分析原文也可以得到正確答案，與colossal并列的詞匯是slow，中間的邏輯關系詞 是but,證明兩者有轉折關系。再經過推斷，緩慢的過程但量 大的話就足以發生巨大的改變。所以選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.根據 Isthmus of Panama 定位。從About開始。本段的 最后一句說了isthmus of Panama帶來的結果，對應了D選項。

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

  A.quality.

  B.order.

  C.function.

  D.number.

  9.高亮詞所在句提到了氨基酸，酶，pairs這些話題，其實就是在說成對的基因，膠體電泳分析揭示了少量的氨基酸的不同。A質量，C 功能，D數量都不對，應該選擇B順序。

  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.跟上面一題對應的位置是一樣的。或者可以根據Graves found定位，閱讀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對應了標注句子，B明顯錯誤，文章一直在說改變。C文章提到 gel electrophoresis的地方只是說氨基酸的順序改變，但沒說both benefited。D文章也沒提到。

  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.原文高亮句翻譯為：格雷夫斯關于地峽魚類地域隔離的種群研究為中性或適應性突變的逐漸累積過程的開始提供了一些線索，這里的差異可能會給正在進行的異域性物種的形成提供證據。所以主干部分為...的研究為..的開始提供了線索，對應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，那么證明句子前面的內容中己經出現了isthmus，而后面則是 要說明consequences。第二個空符合邏輯，所以選擇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

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.

  由于不同社會持有的關于兒童早教目的觀點的不同，學前班(5歲以下兒童的教育項目)的形式在不同國家也大不相同。比如說，在一項中、日、美三國的跨國學前班調査中，調査者發現這三個國家的父母對學前教育的看法大相徑庭。中國的父母大都認為上學前班可以幫孩子們打開學術上的大門，日本父母則把其看做是一個使孩子融入集體的好機會。相比之下，美國父母認為學前班最主要的目的是讓孩子減少依賴性并變得更加自立，盡管獲得一個良好的學業開端和團隊經驗同樣重要。

  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.

  許多為學齡前兒童設計的課程項目主要集中在社會因素和情感因素上，而有些主要是為提升學齡前孩子們的認知能力和給他們提供開始上幼兒園后會經歷的正規指導。在美國，眾所周知，為促進未來學術成功設計的項目叫“Head Start”，在20世紀60年代美國開始“對貧窮開戰”時建立的。這個項目已經為超過13000000孩子和其家庭提供服務。其強調的是家長的參與，為培養“全方位發展的兒童”所設計的，包括孩子的身體健康、自信心、社會責任感以及社交能力與情感的發展。

  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”的成功與否取決于人們看待的角度。比如說，如果人們希望它可以帶來智商的長期増長，那它終將是令人失望。因為，盡管“Head Start”可以使智力迅速地提高，但這種増長并不會持續太久。另一方面，很顯然，“Head Start”的目標是讓學齡前兒童做好上學的準備。相對那些沒參與過“Head Start”計劃的孩子們而言，參加了這個項目的孩子們對學業有著更充分的準備。而且，“Head Start”的畢業生今后的學習成績會更好。最后，調査表明，雖然收獲一般，但最終“Head Start”的畢業生在高中結束時會取得更高的學術成就。

  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，從其他類型的學齡前預備項目的結果來看，那些參加過學前項目的畢業生很少重讀，他們更愿意完成學校而不是預備項目。在畢業生長到27歲時，納稅人在這個項目上曾經花費的每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.

  最近關于早期介入項目的綜合評估表明，總的來說，學前項目可以帶來巨大的收益，政府在早期投入的資金最終會減少未來的花銷。比如說，與沒有參與早期介入項目的孩子相比, 參加了各種項目的孩子在情感和認知能力上得到了提高，改善了教育成果，提高了經濟的自足性，減少了犯罪行為的發生，健康行為得到了改進。當然，不是所有的項目都能產生這樣的收益，也不是每個孩子都能得到同等程度的提高。此外，一些調査者稱那些相對便宜的項目和昂貴項目結果一樣好。評估的結果仍然很樂觀，它認為早期介入的潛在好處是不可估量的。

  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.

  并不是所有人都認為在學前期追求學術上的提高是一件好事。事實上，據發展心理學家 大衛??艾爾凱德所說，美國社會急于催促逼迫孩子，以至于他們年紀小卻感到壓力。艾爾凱德認為學術上的成功主要取決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，如果不考慮特定年齡段孩子們目前的認知發展水平，就不能期待他們掌握教材。總之，孩子們需要發展適當的教育實踐，那就是基于孩子的典型發展和獨特性的教育。

  托福閱讀試題

  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.根據題目中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.這里對比了Chinese和Japanese家長之間的差別，所以A最合適。

  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， 另外這里和focus配合的介詞是on，concentrate也用 on，所以這里幫助推斷。

  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.根據Head Start定位， 后面的內容就是對Head Start這個program的介紹，首先是 I960年開始的，和C矛盾， 然后說是在US宣布了 War on Poverty (貧窮)的時候，所以是為窮人設計的，符合A。 B沒提到，D在這段的開頭提到了，但是不是針對Head Start的描述，Head Start目標 是"whole child"，德智體美勞全面發展。

  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不對應，其他的幾個選項根據后文中的內容都是正確的。

  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定位到本段第一句，本句內容：參加這些 program留級的可能性小，而且還能省錢，所以選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改變了原文意思，B文章沒說只到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，綜合的意思，使用代入法，A最易懂的，B完整的，C值得尊敬的，D客觀的 中，AC可以排除，不通順，B和D之間就需要理解 comprehensive的詞意來確定。

  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.根據關鍵詞定位至For instance開始的內容，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對應 "reduction in future costs〃證明是 long term 的 benefit，所以A錯誤。B對應 "less-expensive programs are just as good as relatively expensive ones〃說明便宜和貴的一樣好，B選項也不對。 C沒提到。D對應not every child benefited to the same extent，正確。

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

  A.claim.

  B.manage.

  C.fail.

  D.attempt.

  11.seek本身是尋找，追求的意思。A是要求，B是設法，管理， C是失敗，D是嘗試，所以D 最合適。

  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.關鍵詞對應后，根據本段的第一句，Elkind是作為反面觀點的例子出現的，所以是為了闡述另外一面的觀點，選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的結構，那么起到的就是承上啟下的作用。句子前面一定出現emotional distress的內容，后面要引出的就是 intended cognitive gains的相關內容，所以選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

  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.

  熱帶草原或熱帶稀樹草原位于熱帶低海拔地區，干濕氣候皆有。稀疏分布著樹木和灌木的廣闊大草原，其為一個穩定的生態系統。氣候極端，涵蓋了廣泛的土壤種類。對于熱帶草原的形成原因，雖無單一的解釋，但似乎仍有一些因素對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.

  熱帶草原通常會經歷十分漫長的旱季。熱帶草原形成理論之一，就是濕潤的森木物種無法承受干燥的季節——這更有利于熱帶草原，而不是熱帶雨林的形成。熱帶草原的年降水量在1000到2000毫米，絕大多數降水都集中在長達5到8個月的雨季中。雖然每年的降水總量充足，但至少會有幾個月幾乎零降水，由此引起的干旱使得該地區最終只適合草地生長。這樣的條件廣泛地分布于南美北部和古巴的大部分地區，但也有例外，比如在中美洲的稀樹大草原，巴西的沿海地區和特立尼達島氣候的類型就不一樣。在這些地區每月的降水量超過了之前定義的降水量范圍，因此還有其他因素影響著熱帶草原的形成。

  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.

  雖然極端，但在大多數特點上，熱帶草原和雨林的土壤還是相似的。比如說，和許多熱帶雨林土壤一樣，熱帶草原的土壤通常為含酸量高的氧化土(某些氧化物礦物占主導)和老成土(這些土壤中不含碳酸鈣，磷、鈣、鎂、鉀這樣的礦物質含量非常低，而鋁的含量卻很高)。有些熱帶草原的土壤潮濕，呈潰水狀態;而有些的土壤卻干燥、多沙、易排水。這看起來矛盾，但卻意味著只有像過度濕潤或過度干旱那樣的極端土壤條件，才適合熱帶草原，溫潤的氣候適合濕潤的森林。

  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.

  潰水土壤出現在地形平坦和排水性差的地方。這些土壤通常含有大量的黏土，這就會使它們很容易處于飽水狀態。由于空氣不能滲入土壤顆粒中，土壤的含氧量就低。與之相對，干燥土壤是多沙和多孔滲水的。它們的粗質結構可以讓水很快排干。砂質土壤更易于營養物和礦物質的過濾滲漏，這就導致土壤缺乏營養。雖然大多數熱帶草原都位于貧瘠土壤區(無論是因為各自的水分條件還是營養等級)，但貧瘠土壤也的確能夠長出繁茂的熱帶雨林。

  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.

  大多數熱帶草原都可能經歷著頻繁的焚燒，而大約兩年就有一次大火燃燒。許多熱帶草原和干燥林的植物種類被叫做耐火植物，意思是其善于用各種方法來抵御偶爾發生的燃燒。雖然追溯到人類初至時亞馬遜森林土壤中遺留的古木碳表明濕潤林帶也會有不定期的燃燒，但頻繁的大火還是熱帶雨林物種所不能適應的因素。實驗表明，如果美國的熱帶草原沒有發生大火，物種的構成就會變得完全不一樣。焚燒的防止了植物之間的競爭，這就避免了因植物間的排擠而使整個生態系統的多樣性發生變化。但是在防火實驗區，一些多年生植物物種最終占得主導地位，勝過了其他物種。其他調査證據表明，沒有焚燒則導致植物物種豐富性的顯著減少，通常還會伴隨著樹的密度増加。這就可以確定，火是維持熱帶草原的重要因素。當然，這指的是在大多數地區。

  【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.

  在某些地區，特別是在南美洲，熱帶草原的形成可能和為了建造牧場而對濕潤林地進行頻繁的砍伐和焚燒有關。牧場的増加和隨之而來的過度放牧導致了熱帶草原的擴張。稀薄的腐殖質(腐爛的有機物)上層被砍伐和焚燒行為所破壞。腐殖質是樹葉被細菌和真菌迅速分解和根部表面循環的必需品。一旦腐面層消失了，營養物質便不能循環并滲入土壤中，土壤由肥沃變得貧瘠，這就使它只適合熱帶草原植被的生長。白土和砂土上的森林結構容易發生永久性的改變。

  托福閱讀試題

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

  A.predictable.

  B.destructive.

  C.lengthy.

  D.unproductive.

  1.可以根據詞根分析，原文中prolonged，詞根為long，長度。Prolonged為延長的。選項中C，length本來是長度的意思，lengthy變為形容詞格式，符合原詞詞義。

  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作為關鍵詞定位到原文，看到這半句和前 半句中間有but的轉折，那么也就是說centralAmerica，Brazil這些地方和前面介紹的不一樣，所以是例外情況。

  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.本段第一句就指出，rain forest和savannas的土壤是相似的，但是更極端一點。后面就給了examples。最后一句 給出了兩種土壤的總結"this may seem….Either too wet or too dry for forests" 所以選 D。

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

  A.similarly.

  B.especially.

  C.usually.

  D.relatively.

  4.Notably從notice發展而來，以為顯著的，因此選擇B。另外也可通過and的并列格式來推斷。

  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.這一題對應for example后面的內容，A直接和紅色標注部分矛盾，因此是要選的except的選項。

  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對于"by contrast…"那一句，sandy soil和waterlogged soils 是相反的。B 與原文矛盾，上段最后就說要么很干要么很濕，waterlogged 就是很濕的那種。C對于那個 making the soil oxygen-poor。D對應"Sandy soils are prone to ....."，而不是選項中說的 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.這句話說雖然幾乎全部 的savannas都發生在poor soils之上，但是poor soils足以支撐茂盛的熱帶雨林。所以是轉折，說明poor soils不是唯一決定了savannas的因素， 還有別的。

  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.原句主干是說frequent fire是造成熱帶雨林不能形成的原因，即使在人類出現之前亞馬遜雨林也出現過偶爾的 燃燒。所以D是意思最完整的。可根據轉折關系來判斷。

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

  A.dangerously.

  B.noticeably.

  C.rapidly.

  D.gradually.

  9.根據詞根判斷，原詞詞根為mark意為標注，跟選項中B的notice意思相近，所以選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.對應部分從but in experimental areas protected from fire開始，后面的內容都對其重要性進行了解釋，如果沒有火來保持savannas，那么就很少有perennial grass species可以outcompeting其他的種類，從而減少了plant-species的豐富，而樹的密度則會更大。對應了 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就是后來，然后的意思。因此選擇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，然后這句的后面，從''increase....''開始就是后果。先說humus is destroyed，對應 C，然后 humus 對于decomposition是非常必 要的，而 human activitydestroy了humus，所以減慢了decomposition，和A矛盾。 后面說 nutrients cannot被recycled，對應了B。converting那一句對應了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，并且開頭是in addition，證明是對前面句子的補充，前面句子說的應該是savannas形成的原因之一，對應了第二句。并且第三空后面的句子提到了cutting和burning，這些都是human activity。所以選 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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