一般以閱讀時是否出聲音為標準，則可以分為朗讀、默讀和視讀三類，前兩類也稱為音讀，后一類一般稱為速讀。以下是學習啦小編為大家精心準備的：托福TPO31閱讀答案，歡迎參考閱讀!

　　托福TPO31文章閱讀：

　　Evolutionary biologists believe that speciation, the formation of a new species, often　begins when some kind of physical barrier arises and divides a population of a single　species into separate subpopulations. Physical separation between subpopulations　promotes the formation of new species because once the members of one subpopulation　can no longer mate with members of another subpopulation, they cannot exchange　variant genes that arise in one of the subpopulations. In the absences of gene flow　between the subpopulations, genetic differences between the groups begin to accumulate　Eventually the subpopulations become so genetically distinct that they cannot interbreed　even if the physical barriers between them were removed. At this point the subpopulations　have evolved into distinct species. This route to speciation is known as allopatry (“allo-”　means “different”, and “patria” means “homeland”)

　　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 are　separated from each other by some measurable distance. So even under normal　situations the gene flow among the subpopulations is more of an intermittent trickle than a　steady stream. In addition, barriers can rapidly arise and shut off the trickle. For example,　in the 1800s a monstrous earthquake changed the course of the Mississippi River, a large　river flowing in the central part of the United States of America. The change separated　populations of insects now living along opposite shore, completely cutting off gene flow　between them.

　　Geographic isolation also can proceed slowly, over great spans of time. We find evidence　of such extended events in the fossil record, which affords glimpses into the breakup of　formerly continuous environments. For example, during past ice ages, glaciers advanced　down through North America and Europe and gradually cut off parts of populations from　one another. When the glacier retreated, the separated populations of plants and animals　came into contact again. Some groups that had descended from the same parent　population were no longer reproductively compatible — they had evolved into separate　species. In other groups, however, genetic divergences had not proceeded so far, and the　descendants could still interbreed — for them, reproductive isolation was not completed,　and so speciation had not occurred.

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

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

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

　　托福TPO31閱讀題：

　　1. The word “promotes” in the passage is closest in meaning to

　　A. describes

　　B. encourages

　　C. delays

　　D. requires

　　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.

　　3. Why does the author provide the information that “the subpopulations of most species　are separated from each other by some measurable distance”?

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

　　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.

　　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

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

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

　　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 a　species happens at a slow rate.

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

　　6. According to paragraph 3, separation of subpopulations by glaciers resulted in　speciation 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.

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

　　A. consistent　　B. gradual　　C. enormous　　D. effective

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

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

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

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

　　E. The movements created conditions for the formation of new species of fishes and　other marine animals.

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

　　A. quality　　B. order　　C. function　　D. number

　　10. According to paragraph 5, by comparing the enzymes from two related groups of　fishes 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　the Pacific group of fishes

　　11. It can be inferred from paragraph 5 and 6 that the reason Graves concluded that some　of the differences between the Pacific and Atlantic enzymes were not random was 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　the Isthmus of Panama

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

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

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

　　A. Graves’s study provides evidence that isthmus fishes are in the process of becoming　geographically isolated.

　　B. Graves’s study of mutating isthmus fishes yields results that differ from results of other　studies involving allopatric speciation.

　　C. Graves’s study of isolated populations of isthmus fishes provides some evidence that allopatric speciation might be beginning

　　D. Grave’s study indicates that when isolated, populations of isthmus fished register　neutral or adaptive mutations.

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

　　Allopatric speciation takes place when physically separated populations of a　single species gradually diverge genetically to the point of becoming unable to　interbreed　　Answer Choices

　　A. Allopatric speciation is common because the gene flow between subpopulations is　generally limited and the barriers that completely separate subpopulations can arise in　a variety of ways.

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

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

　　D. Physical barriers from glaciers and the movement of tectonic plates form so slowly　that the subpopulations 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 a picture of the beginning stages of speciation.

　　F. Graves’s study of physically separated fish populations show that there must be large　differences between the environments of the isolated populations if allopatric　speciation is to take place.

　　托福TPO31閱讀題答案：

　　1. B　　2. D　　3. D　　4. C　　5. B　　6. A　　7. C　　8. D　　9. B　10. A　　11. A　　12. C　　13. B　　14. ABE

　　托福TPO31答案解析：

　　第一題，B，詞匯題。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。

　　第二題，D，細節題。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。

　　第三題，D，作者意圖題。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。

　　第四題，C，詞匯題。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。怎么怎么樣了，最終達到了后面這句的效果。那么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。

　　第五題，B，修辭目的題。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。

　　第六題:，A，事實信息題。根據 Glaciers 和 plants and animals 定位。紅色句子就是glacier separation 導致的結果。所以對應選項 A。

　　第七題，C，詞匯題。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。

　　第八題，D，事實信息題。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。

　　第九題，B，詞匯題。高亮詞所在句提到了氨基酸啊，酶啊，pairs 啊什么的，其實就是在說成對的基因呀，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。(了解一點生物相關知識就很容易明白啦)而且sequence 本身也是序列，順序的意思。

　　第十題，A，詞匯題。跟上面一題對應的位置是一樣的。或者可以根據 Graves found 定位，閱讀后面的部分可以很容易得出答案 A。

　　第十一題，A，推斷題。A對應了第五段紅色標注句子，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了，但沒說 both benefited。D 文章也沒提到。

　　第十二題，C，句子簡化題。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。

　　第十三題，B，句子插入題。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已經出現了 isthmus，而后面則是要說明 consequences。第二個空符合邏輯，所以選擇 B。

　　第十四題，ABE，文章小結題。A對應文章第二段;B對應文章第第三段;C錯誤，與文章多出矛盾，文章一直在強調allopatry 是最主要的speciation route;D錯誤，對應文章第三段，可參考詞匯題colossal 的分析，文章中不僅提到了 Slow 也說到的大量，從而導致了 distinct species;E與 12 題的對應的位置一樣;F錯誤，與文章中詞匯題 sequence 所再句矛盾，那一句提到了 slight difference。

　　托福閱讀TPO31原參考譯文：在地理上隔離的種群的形態

　　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(“allo-”意思是“不同的”“patria”意為“故鄉”)。

　　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了。一般而言，大多數的物種的亞種族都是被遙遠距離所隔開了。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，彼此的基因流動已經完全被截斷了。

　　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。

　　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障礙。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。

　　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。

　　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。