托福阅读事实信息题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的事实信息题及其对应的解析，供大家参考使用。本文带来的是 TPO33-3的事实信息题，一起来看看吧。
TPO33-3Extinction Episodes of the Past
【1】It was not until the Cambrian period, beginning about 600 million years ago, that a greatproliferation of macroscopic species occurred on Earth and produced a fossil record that allows us to track the rise and fall of biodiversity. Since the Cambrian period, biodiversity has generally risen, but there have been some notable exceptions. Biodiversity collapsed dramatically during at least five periods because of mass extinctions around the globe. The five major mass extinctions receive most of the attention, but they are only one end of a spectrum of extinction events. Collectively, more species went extinct during smaller events that were less dramatic but more frequent. The best known of the five major extinction events, the one that saw the demise of the dinosaurs, is the Cretaceous-Tertiary extinction.
2. Paragraph 1 supports which of the following statements about life on Earth before the Cambrian period?
A) Biodiversity levels were steady, as indicated by the fossil record.
B) Levels of biodiversity could not be tracked.
C) The most dramatic extinction episode occurred.
D) Few microscopic species existed.
.答案 B
解析：定位句It was not until the Cambrian period, beginning about 600 million years ago, that a great proliferation of macroscopic species occurred on Earth and produced a fossil record that allows us to track the rise and fall of biodiversity. 主要意思是直到寒武纪才能够监测生物多样性。言外之意就是在寒武纪之前就不能监测生物多样性, 对应B选项。
【2】Starting about 280 million years ago, reptiles were the dominant large animals in terrestrial environments. In popular language this was the era “when dinosaurs ruled Earth,” when a wide variety of reptile species occupying many ecological niches. However, no group or species can maintain its dominance indefinitely, and when, after over 200 million years, the age of dinosaurs came to a dramatic end about 65 million years ago, mammals began to flourish, evolving from relatively few types of small terrestrial animals into the myriad of diverse species, including bats and whales, that we know today. Paleontologists label this point in Earth’s history as the end of the Cretaceous period and the beginning of the Tertiary period, often abbreviated as the K-T boundary. This time was also marked by changes in many other types of organisms. Overall, about 38 percent of the families of marine animals were lost, with percentages much higher in some groups Ammonoid mollusks went from being very diverse and abundant to being extinct. An extremely abundant set of planktonic marine animals called foraminifera largely disappeared, although they rebounded later. Among plants, the K-T boundary saw a sharp but brief rise in the abundance of primitive vascular plants such as ferns, club mosses, horsetails, and conifers and other gymnosperms. The number of flowering plants (angiosperms) was reduced at this time, but they then began to increase dramatically.
5. According to paragraph 2, which of the following species initially increased in number at the K-T boundary?
A) Dinosaurs
B) Foraminifera
C) Ferns
D) Ammonoid mollusks
答案 D
解析：定位句Paleontologists label this point in Earth‟s history as the end of the Cretaceous period and the beginning of the Tertiary period, often abbreviated as the K-T boundary. This time was also marked by changes in many other types of organisms. Overall, about 38 percent of the families of marine animals were lost, with percentages much higher in some groups Ammonoid mollusks went from being very diverse and abundant to being extinct. 题干中的范围限定initially, 因此只可能是Ammonoid mollusk, 选D。
【4】Explanations for the K-T extinction were revolutionized in 1980 when a group of physical scientists led by Luis Alvarez proposed that 65 million years ago Earth was stuck by a 10-kilometer-wide meteorite traveling at 90,000 kilometers per hour. They believed that this impact generated a thick cloud of dust that enveloped Earth, shutting out much of the incoming solar radiation and reducing plant photosynthesis to very low levels. Short-term effects might have included huge tidal waves andextensive fires. In other words, a series of events arising from a single cataclysmic event caused the massive extinctions. Initially, the meteorite theory was based on a single line of evidence. At locations around the globe, geologists had found an unusually high concentration of iridium in the layer of sedimentary rocks that was formed about 65 million years ago. Iridium is an element that is usually uncommon near Earth’s surface, but it is abundant in some meteorites. Therefore, Alvarez and his colleagues concluded that it was likely that the iridium in sedimentary rocks deposited at the K-T boundary had originated in a giant meteorite or asteroid. Most scientist came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.
10. According to paragraph 4, which of the following statements explains the importance of the discovery of high levels of iridium rocks?
A) It provided evidence that overexposure to solar radiation led to the K-T extinction.
B) It showed that more than one cataclysmic event was responsible for the K-T extinction.
C) It suggested that the cause of the K-T extinction may have been a meteorite striking Earth.
D) It provided evidence that the K-T extinction occurred 65 million years ago.
答案 C
解析：定位句Initially, the meteorite theory was based on a single line of evidence. At locations around the globe, geologists have found an unusually high concentration of iridium in the layer of sedimentary rocks that was formed about 65 million years ago. 意思是说小行星撞击理论一开始主要的证据就是在地球的岩石中发现了大量的iridium (铱)。因此其重要性就是说明该撞击理论是物种大灭绝的原因。
【4】Explanations for the K-T extinction were revolutionized in 1980 when a group of physical scientists led by Luis Alvarez proposed that 65 million years ago Earth was stuck by a 10-kilometer-wide meteorite traveling at 90,000 kilometers per hour. They believed that this impact generated a thick cloud of dust that enveloped Earth, shutting out much of the incoming solar radiation and reducing plant photosynthesis to very low levels. Short-term effects might have included huge tidal waves andextensive fires. In other words, a series of events arising from a single cataclysmic event caused the massive extinctions. Initially, the meteorite theory was based on a single line of evidence. At locations around the globe, geologists had found an unusually high concentration of iridium in the layer of sedimentary rocks that was formed about 65 million years ago. Iridium is an element that is usually uncommon near Earth’s surface, but it is abundant in some meteorites. Therefore, Alvarez and his colleagues concluded that it was likely that the iridium in sedimentary rocks deposited at the K-T boundary had originated in a giant meteorite or asteroid. Most scientist came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.
11. According to paragraph 4, which of the following is true about the Yucatan Peninsula?
A) The circular formation there was caused by a meteorite impact 65 million years ago.
B) Sedimentary rocks from that area have the lowest iridium concentration of any rocks on Earth.
C) There is evidence that a huge tidal wave occurred there 65 million years ago.
D) Evidence found there challenged the meteorite impact theory.
答案 A
解析：定位句Most scientists came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago. 意思是说在Yucatan Peninsula背岸的大坑是陨石撞击的结果，对应A选项。
以上就是托福阅读TPO33-3中的事实信息题及其解析，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
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