托福TPO8阅读真题Part2文本及题目答案
According to paragraph 1, which of the following is true of the Late Cretaceous climate?
○Summers were very warm and winters were very
○Shallow seas on the continents caused frequent temperature
○The climate was very similar to today's
○The climate did not change dramatically from season to
Paragraph 2: At the end of the Cretaceous, the geological record shows that these seaways retreated from the continents back into the major ocean No one knows Over a period of about 100,000 years, while the seas pulled back, climates around the world became dramatically more extreme: warmer days, cooler nights; hotter summers, colder Perhaps dinosaurs could not tolerate these extreme temperature changes and became
Which of the following reasons is suggested in paragraph 2 for the extinction of the dinosaurs?
○Changes in the lengths of the days and nights during the late Cretaceous period
○Droughts caused by the movement of seaways back into the oceans
○The change from mild to severe climates during the Late Cretaceous period
○An extreme decrease in the average yearly temperature over 10,ooo years
Paragraph 3: If true, though, why did cold-blooded animals such as snakes, lizards, turtles, and crocodiles survive the freezing winters and torrid summers? These animals are at the mercy of the climate to maintain a livable body It's hard to understand why they would not be affected, whereas dinosaurs were left too crippled to cope, especially if, as some scientists believe, dinosaurs were Critics also point out that the shallow seaways had retreated from and advanced on the continents numerous times during the Mesozoic, so why did the dinosaurs survive the climatic changes associated with the earlier fluctuations but not with this one? Although initially appealing, the hypothesis of a simple climatic change related to sea levels is insufficient to explain all the
Why does the author mention the survival of "snakes, lizards, turtles, and crocodiles" in paragraph 3?
○To argue that dinosaurs may have become extinct because they were not cold-blooded animals
○To question the adequacy of the hypothesis that climatic change related to sea levels caused the extinction of the dinosaurs
○To present examples of animals that could maintain a livable body temperature more easily than dinosaurs
○To support a hypothesis that these animals were not as sensitive to climate changes in the Cretaceous period as they are today
The word "cope" in the passage is closest in meaning to
○ adapt
○ move
○ continue
○ compete
According to paragraph 3, which of the following is true of changes in climate before the Cretaceous period and the effect of these changes on dinosaurs?
○Climate changes associated with the movement of seaways before the Cretaceous period did not cause dinosaurs to become
○Changes in climate before the Cretaceous period caused severe fluctuations in sea level, resulting in the extinction of the
○Frequent changes in climate before the Cretaceous period made dinosaurs better able to maintain a livable body
○Before the Cretaceous period there were few changes in climate, and dinosaurs
word "fluctuations" in the passage is closest in meaning to
○ extremes
○ retreats
○ periods
○ variations
Paragraph 4: Dissatisfaction with conventional explanations for dinosaur extinctions led to a surprising observation that, in turn, has suggested a new Many plants and animals disappear abruptly from the fossil record as one moves from layers of rock documenting the end of the Cretaceous up into rocks representing the beginning of the Cenozoic (the era after the Mesozoic). Between the last layer of Cretaceous rock and the first layer of Cenozoic rock, there is often a thin layer of Scientists felt that they could get an idea of how long the extinctions took by determining how long it took to deposit this one centimeter of clay and they thought they could determine the time it took to deposit the clay by determining the amount of the element iridium (lr) it
Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? In correct choices change the meaning in important ways or leave out essential
○The fossil record suggests that there was an abrupt extinction of many plants and animals at the end of the Mesozoic
○Few fossils of the Mesozoic era have survived in the rocks that mark the end of the
○Fossils from the Cretaceous period of the Mesozoic up to the beginning of the Cenozoic era have been removed from the layers of rock that surrounded
○Plants and animals from the Mesozoic era were unable to survive in the Cenozoic
Paragraph 4: Dissatisfaction with conventional explanations for dinosaur extinctions led to a surprising observation that, in turn, has suggested a new Many plants and animals disappear abruptly from the fossil record as one moves from layers of rock documenting the end of the Cretaceous up into rocks representing the beginning of the Cenozoic (the era after the Mesozoic). Between the last layer of Cretaceous rock and the first layer of Cenozoic rock, there is often a thin layer of Scientists felt that they could get an idea of how long the extinctions took by determining how long it took to deposit this one centimeter of clay and they thought they could determine the time it took to deposit the clay by determining the amount of the element iridium (Ir) it
In paragraph 4, all the following questions are answered EXCEPT:
○Why is there a layer of clay between the rocks of the Cretaceous and Cenozoic?
○Why were scientists interested in determining how long it took to deposit the layer of clay at the end of the Cretaceous?
○What was the effect of the surprising observation scientists made?
○Why did scientists want more information about the dinosaur extinctions at the end of the Cretaceous?
Paragraph 5: Ir has not been common at Earth's since the very beginning of the planet's Because it usually exists in a metallic state, it was preferentially incorporated in Earth's core as the planet cooled and Ir is found in high concentrations in some meteorites, in which the solar system's original chemical composition is Even today, microscopic meteorites continually bombard Earth, falling on both land and By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of Ir in the boundary These calculations suggest that a period of about one million years would have been However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million So the unusually high concentration of Ir seems to require a special
The word "bombard" in the passage is closest in meaning to
○ approach
○ strike
○ pass
○ circle
Paragraph 5 implies that a special explanation of Ir in the boundary clay is needed because
○the Ir in microscopic meteorites reaching Earth during the Cretaceous period would have been incorporated into Earth's core
○the Ir in the boundary clay was deposited much more than a million years ago
○the concentration of Ir in the boundary clay is higher than in microscopic meteorites
○the amount of Ir in the boundary clay is too great to have come from microscopic meteorites during the time the boundary clay was deposited
Paragraph 6: In view of these facts, scientists hypothesized that a single large asteroid, about 10 to 15 kilometers across, collided with Earth, and the resulting fallout created the boundary Their calculations show that the impact kicked up a dust cloud that cut off sunlight for several months, inhibiting photosynthesis in plants; decreased surface temperatures on continents to below freezing; caused extreme episodes of acid rain; and significantly raised long-term global temperatures through the greenhouse This disruption of food chain and climate would have eradicated the dinosaurs and other organisms in less than fifty
The word "disruption" in the passage is closest in meaning to
○ exhaustion
○ disturbance
○ modification
○ disappearance
Paragraph 6 mentions all of the following effects of the hypothesized asteroid collision EXCEPT
○ a large dust cloud that blocked sunlight
○ an immediate drop in the surface temperatures of the continents
○ an extreme decrease in rainfall on the continents
○ a long-term increase in global temperatures
Paragraph 5: Ir has not been common at Earth's since the very beginning of the planet's Because it usually exists in a metallic state, it was preferentially incorporated in Earth's core as the planet cooled and Ir is found in high concentrations in some meteorites, in which the solar system's original chemical composition is Even today, microscopic meteorites continually bombard Earth, falling on both land and By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of Ir in the boundary ■ These calculations suggest that a period of about one million years would have been ■However, other reliable evidence suggests that the deposition of the boundary clay could not have taken one million ■So the unusually high concentration of Ir seems to require a special ■
Look at the four squares [■] that indicate where the following sentence could be added to the
Consequently, the idea that the Ir in the boundary clay came from microscopic meteorites cannot be
Where would the sentence best fit?
Directions: An introductory sentence for a brief summary of the passage is provided Complete the summary by selecting the THREE answer choices that express the most important ideas in the Some sentences do not belong in the summary because they express that are not presented in the passage or are minor ideas in the This question is worth 2
For a long time scientists have argued that the extinction of the dinosaurs was related to climate
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●
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Answer choices
○A simple climate change does not explain some important data related to the extinction of the dinosaurs at the end of the
○The retreat of the seaways at the end of the Cretaceous has not been fully
○The abruptness of extinctions at the end of the Cretaceous and the high concentration of Ir found in clay deposited at that time have fueled the development of a new
○Extreme changes in daily and seasonal climates preceded the retreat of the seas back into the major ocean
○Some scientists hypothesize that the extinction of the dinosaurs resulted from the effects of an asteroid collision with
○Boundary clay layers like the one between the Mesozoic and Cenozoic are used by scientists to determine the rate at which an extinct species declined