官方真题Official5托福阅读Passage3原文文本+真题+答案解析

官方真题Official5托福阅读Passage3题目

Question 1 of 14

The word “significant ” in the passage is closest in meaning to

A. numerous

B. important

C. unexplained

D. sudden

Question 2 of 14

The word “relatively ” in the passage is closest in meaning to

A. surprisingly

B. collectively

C. comparatively

D. characteristically

Question 3 of 14

The word “diversification ” in the passage is closest in meaning to

A. emergence of many varieties

B. steady decline in number

C. gradual increase in body size

D. sudden disappearance

Question 4 of 14

The period discussed in the passage is referred to as an “explosion ” because it

A. occurred 0.6 billion years ago, late in Earth’s history

B. was characterized by the unusually fast evolution of many new life-forms

C. was characterized by widespread animal extinction

D. was characterized by violent volcanic eruptions

Question 5 of 14

According to Paragraph2, which of the following is NOT a question that paleontologists asked about the Cambrian explosion?

A. Why was the origin of life a simple step in Earth’s history?

B. Why did it take so long for multicellular organisms to develop?

C. Why did animal life evolve so rapidly?

D. Why does the fossil record lack evidence of animal evolution during that time?

Question 6 of 14

Which of the following best describes the relationship between paragraph 2 and paragraph 3?

A. Paragraph 2 puts forward several scientific claims, one of which is rejected in paragraph 3.

B. Paragraph 2 poses several questions, and paragraph 3 offers a possible answer to one of them.

C. Paragraph 2 presents outdated traditional views, while paragraph 3 presents the current scientific conclusions

.D. Paragraph 2 introduces a generalization that is illustrated by specific examples in paragraph 3.

Question 7 of 14

The word “promote ” in the passage is closest in meaning to

A. complicate

B. prevent

C. encourage

D. affect

Question 8 of 14

Which of the following is NOT mentioned in paragraph 4 as being true of the Ediacara formation?

A. It contains fossils that date back to the Precambrian period.

B. It contains only soft-bodied animal fossils.

C. It is located on a single site in Australia.

D. It does not contain any fossils of the ancestors of modern animals.

Question 9 of 14

Which of the sentences 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. The animals found in the Tommotian fossil bed were once thought to belong to a variety of modern animal groups, but now they are thought to have descended from a single group.

B. Animals in the Tommotian fossil beds were initially assigned to modern animal groups but are now thought to belong to groups that emerged and died out during the Cambrian period.

C. Though at first they thought otherwise, paleontologists now agree that the animals in the Tommotian have body forms from which modern animals have descended.

D. It is unclear whether the Tommotian fossils from the early Cambrian period represent unique body forms or whether they should be assigned to various modern animal groups.

Question 10 of 14

Why does the author mention “Anomalocaris” and “Wiwaxia”?

A. To contrast predators with animals that eat plants such as algae

B. To question the effects of rapid mud slides on fossilization

C. To suggest that much is still unknown about animals found in the Burgess Shale

D. To provide examples of fossils that cannot be assigned to a modern animal group

Question 11 of 14

“Sidneyia ” is an example of

A. a relative of Anomalocaris and Wiwaxia

B. a previously unknown Burgess Shale animal

C. an extinct member of a currently existing category of animals

D. an animal that cannot be assigned to any modern animal group

Question 12 of 14

What can be inferred from paragraph 7 about why the Cambrian explosion is so unusual?

A. It generated new ecological niches through the extinction of many unique animals.

B. It was a period of rapid evolution, and evolution is often thought of as a slow process.

C. It is a period whose evolutionary sequences are clearly marked.

D. It generated a very large number of ancient fossil beds containing soft-bodied animals.

Question 13 of 14

Look at the four squares [■] that indicate where the following sentence could be added to the passage.Where could the sentence best fit?

It is relatively rare because the fossilization of soft-bodied animals requires a special environment..

Question 14 of 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 answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points. The term “Cambrian explosion” refers to the geologically brief period during which all modern animal groups evolved.

A.Little is known about the stages of evolution during the Cambrian period, in part because early animals were soft bodied and could fossilize only under particular conditions.

B.While animal fossils from before the Cambrian explosion have no modern descendants, many animals that evolved during the Cambrian explosion can be assigned to modern groups.

C.The Cambrian period is significant because it marks the emergence of eukaryotic life-forms—organisms that have cells with true nuclei.

D.The Ediacara fossil formation provides the most information about the Cambrian explosion, while the earlier, Tommotian and Burgess Shale formations give clues about Precambrian evolution.

E.Zoologists are awaiting the discovery of a 600-million-year-old fossil formation in order to be able to form a theory of how animal evolution progressed.

F.Although the reasons for the rapid evolution of animals during the Cambrian period are not known, one proposed explanation is an abundance of niches with a lack of competitors.

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