Life originated in the early seas less than a billion years after Earth was formed. Yet another three billion years were to pass before the first plants and animals appeared on the continents
Câu hỏi:
Life originated in the early seas less than a billion years after Earth was formed. Yet another three billion years were to pass before the first plants and animals appeared on the continents. Life's transition from the sea to the land was perhaps as much of an evolutionary challenge as was the genesis of life.
What forms of life were able to make such a drastic change in lifestyle? The traditional view of the first terrestrial organisms is based on megafossils ― relatively large specimens of essentially whole plants and animals. Vascular plants, related to modern seed plants and ferns, left the first comprehensive megafossil record. Because of this, it has been commonly assumed that the sequence of terrestrialization reflected the evolution of modern terrestrial ecosystems. In this view, primitive vascular plants first colonized the margins of continental waters, followed by animals that fed on the plants, and lastly by animals that preyed on the plant-eaters. Moreover, the megafossils suggest that terrestrial life appeared and diversified explosively near the boundary between the Silurian and the Devonian periods, a little more than 400 million years ago.
Recently, however, paleontologists have been taking a closer look at the sediments below this Silurian-Devonian geological boundary. It turns out that some fossils can be extracted from these sediments by putting the rocks in an acid bath. The technique has uncovered new evidence from sediments that were deposited near the shores of the ancient oceans ― plant microfossils and microscopic pieces of small animals. In many instances the specimens are less than one-tenth of a millimeter in diameter. Although they were entombed in the rocks for hundreds of millions of years, many of the fossils consist of the organic remains of the organism.
These newly discovered fossils have not only revealed the existence of previously unknown organisms, but have also pushed back these dates for the invasion of land by multicellular organisms. Our views about the nature of the early plant and animal communities are now being revised. And with those revisions come new speculation about the first terrestrial life-forms.
The word “drastic” in line 5 is closest in meaning to
A. widespread
B. radical
C. progressive
D. risky
Trả lời:
Lời giải:
Đáp án: B
1. drastical = radical: triệt để
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Câu 1:
Mark the letter A, B, C or D to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
The changing physical landscape reflected the shift to an urbanized society. Railroad terminals, factories, skyscrapers, apartment houses, streetcars, electric engines, department stores, and the increased pace of life were all signs of an emerging urban America.
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Câu 2:
My father said to me “Why are you late? Did you miss the train?”
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Câu 3:
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 39 to 46.
Because writing has become so important in our culture, we sometimes think of it as more real than speech. A little thought, however, will show why speech is primary and writing secondary to language. Human beings have been writing (as far as we can tell from surviving evidence) for at least 5000 years; but they have been talking for much longer, doubtless ever since there have been human beings.
When writing did develop, it was derived from and represented speech, although imperfectly. Even today there are spoken languages that have no written form. Furthermore, we all learn to talk well before we learn to write; any human child who is not severely handicapped physically or mentally will learn to talk: a normal human being cannot be prevented from doing so. On the other hand, it takes a special effort to learn to write. In the past many intelligent and useful members of society did not acquire the skill, and even today many who speak languages with writing systems never learn to read or write, while some who learn the rudiments of those skills do so only imperfectly.
To affirm the primacy of speech over writing is not, however, to disparage the latter. One advantage writing has over speech is that it is more permanent and makes possible the records that any civilization must have. Thus, if speaking makes us human, writing makes us civilized.
We sometimes think of writing as more real than speech because ______.
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Câu 5:
According to the theory that the author calls “the traditional view,” what was the first form of life to appear on land?
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Câu 6:
According to the passage, what happened about 400 million years ago?
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Câu 7:
The word “extracted” in line 18 is closest in meaning to
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Câu 8:
What can be inferred from the passage about the fossils mentioned in lines 17-20?
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