Shoemaker's field studies showed that a completely different situation exists at Meteor Crater, where the ejecta form an inverted flap, flung out and overturned in a single blast.舒梅克的实地研究表明,陨石坑中存在着完全不同的情况,那里的喷出物形成了一个倒置的襟翼,在一次爆炸中被抛出并倾覆。
Thus, a drill hole through the ejecta on the rim would pass through layers of the same material twice. 因此,通过边缘喷出物的钻孔将两次穿过相同的材料层。
From their discovery in 1609 until recently, lunar craters were almost
unanimously thought to have volcanic origins, even though the topography of
the Moon and its craters had been studied minutely by generations of
observers. Dissenting voices, such as that of Robert Hooke, who postulated in
1665 that they were formed by the impact of meteors, did little to sway the
majority opinion. The most serious challenge to the volcanic-formation
the hypothesis was made in 1893 by the geologist G. K. Gilbert. After analyzing
the depth-to-diameter ratios of craters, Gilbert suggested that the craters could
have been formed only by the impact of meteors. The central peaks that were
commonly observed resulted from the rebound of rock, in a similar manner to
liquids (think of drops of water hitting a puddle). Bright rays surrounded many
craters that were formed from material flung out during the impact-impact ejecta.
1. The word “Dissenting" in the passage is closest in meaning to
A. confusing B. forceful C. opposing D. respected
2. The author mentions “drops of water hitting a puddle" in the passage for which of the following reasons?
A. To illustrate the behavior of liquids under pressure
B. To demonstrate common eruption patterns of volcanoes
C. To help readers perceive flaws in G. K. Gilbert's ideas
D. To help readers imagine how lunar craters formed
问题1 2
【1】dissenting=opposing 反对的
【2】滴水穿石形成一个洞
Paragraph 2
Although impacts with a surface can occur at all angles, from less than 5° to
90°, early experiments suggested that only vertical (90°) impacts were capable
of producing circular craters. So the main argument against an impact
mechanism for lunar crater formation was that only circular craters could be
seen on the Moon. However, Gilbert himself showed that the average impact
angle was 45°-in fact, very few impacts were close to vertical.
3. According to paragraphs 1 and 2, which of the following seemed to disprove Gilbert's theory of lunar crater creation?
A. Only circular craters could be seen on the Moon.
B. The impact of meteors striking the Moon could not be observed.
C. Impact craters like those on Earth are not visible on the Moon.
D. Materials surrounding the lunar craters were volcanic in origin.
问题3
黄色高亮部分
月球上有很多形状的陨石坑,不仅仅只有圆形⭕️
Paragraph 3
In 1916 E. J. Öpik published work that recognized that the impact of meteors at
very high velocities would be fundamentally different from the impact at low
velocities created in early laboratory experiments. Such high-velocity impacts
would have a similar effect to an explosion, and craters would be circular even
at low-impact angles. Nevertheless, the volcanic hypothesis remained intact,
and there was significant unwillingness amongst the scientific community
about accepting impact cratering. This began to change in the 1960s with the
work of the American geologist Gene Shoemaker, who made a lifetime study
of cratering.
4. According to paragraph 3, what was E. J. Öpik's contribution to the study of craters?
A. Öpik's work disproved the idea that the average meteor impact angle on the Moon was 45°.
B. Öpik's work showed that circular craters could be formed by meteors impacting the Moon at low angles.
C. Öpik's work suggested that the craters on the Moon may have had several causes.
D. Öpik's work proved that only high-velocity impacts at 90° could have caused lunar craters.
5. According to paragraph 3, which of the following best describes the impact of a meteor striking at a high velocity?
A. It is similar in its effects to those of a low-velocity impact.
B. It creates irregular craters at low-impact angles.
C. It causes a volcanic reaction.
D. It has an effect similar to an explosion.
问题4 5
黄色高亮部分
EJ发现高速撞击类似于爆炸,即使在低角度撞击下也会产生圆形的陨石坑。——>B ✅
——> D ✅
Paragraph 4
Of the 170 known impact craters on the Earth, Meteor Crater in Arizona was
one of the first to be recognized as being formed from an impact. In 1906 D. M.
Barringer provided good evidence for impact formation. However, Meteor
Crater was not universally accepted as an impact crater until the 1960s. Its
impact origin was finally demonstrated in papers published in 1960 and 1963
by Shoemaker. Three lines of evidence show that an impact, and not a
volcanic eruption, formed Meteor Crater.
Paragraph 5
First, as Barringer had recognized many large fragments from an impact have
been found on the desert plains surrounding Meteor Crater. Impact structures
that are larger than Meteor Crater do not usually preserve fragments of the
original projectiles because they vaporize on impact.
Paragraph 6
In addition, most volcanic craters are formed by sustained compression of
volcanic gases, which blast out large volumes of fragments. Volcanic ejecta
form simple aprons around craters, the first-erupted materials at the bottom
and the last at the top. Shoemaker's field studies showed that a completely
different situation exists at Meteor Crater,【7C】where the ejecta form an inverted
flap, flung out and overturned in a single blast. Thus, a drill hole through the
ejecta on the rim would pass through layers of the same material twice. In
Shoemaker's words, the strata appeared to “have been peeled back from the
area of the crater, somewhat like petals of a flower blossoming.”Similar structures
are observed in laboratory experiments involving hypervelocity impacts. 【7D】
6. The word “sustained” in the passage is closest in meaning to
A. delayed B. occasional C. constant D. intense
7. Select the TWO answer choices that name things mentioned in paragraph 6 that involved structures resembling a blossoming flower. To receive credit, you must select TWO answers.
A. Volcanic craters B. Drill holes C. Meteor Crater
D. Certain laboratory experiments
问题6 7
【6】sustained=constant
【7】C D
Paragraph 7
The final piece of evidence comes from an investigation of the effects of the
intense pressures involved in an impact. At Meteor Crater, shattered target
rocks are cemented together by glass at depths of 200-400 meters. The glass
is formed by melting the target during the impact. Melting occurs principally
as a result of the very high pressures involved during an impact, and because
the pressure is applied almost instantaneously, it is referred to as shock
pressure. Unusual high-pressure minerals are often found in the rocks affected
by the impact. These minerals are produced by shock pressure during the impact.
In 1962 Shoemaker made a case for the impact formation of Copernicus
Crater, one of the most prominent craters on the near side of the Moon.// Before
the decade was out, most scientists had come to accept that lunar craters
were formed by impact rather than volcanism. 在那个十年结束之前,
大多数科学家已经开始接受月球陨石坑是由撞击而不是火山作用形成的观点。
8. According to paragraph 7, the shock of a meteor impact causes all of the following to occur in the area EXCEPT
A. melting of rocks B. creation of unusual materials
C. reduction in pressure intensity D. formation of glass underground
问题8
shock pressure=intense pressure
C increasing
P4-问题9
9. Look at the four squares [] that indicate where the following sentence could be added to the passage.
For example, large quantities of meteoric iron were identified around the crater rim and on the surrounding plain.
Where would the sentence best fit? Click on a square to add the sentence to the passage.
Of the 170 known impact craters on the Earth, Meteor Crater in Arizona was
one of the first to be recognized as being formed from an impact. In 1906 D. M.
Barringer had provided good evidence for impact formation. However,
Meteor Crater was not universally accepted as an impact crater until the 1960s.
Its impact origin was finally demonstrated in papers published in 1960 and
1963 by Shoemaker. Three lines of evidence show that an impact, and not a
volcanic eruption, formed Meteor Crater.
evidence——>eg——however, not accepted
全篇-问题10
10. 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 passage or are minor ideas in the passage. This question is worth 2 points. Drag your choices to the spaces where they belong. To review the passage, click on View Text.
Through much of the twentieth century, scientists disagreed on how lunar craters were formed.
A. Over the years, the prevailing belief that lunar craters were formed by volcanic activity was challenged by proponents of the meteor impact theory of crater formation.
B. The most widely accepted explanation of lunar crater formation was the theory proposed in 1893 by the geologist G. K. Gilbert.
C. Because G. K. Gilbert's research showed that the average impact angle of meteors was 45°, he abandoned his own theory of lunar crater formation.
D. The research of D. M. Barringer and Gene Shoemaker provided solid evidence supporting impact formation and was a major factor in discrediting the volcanic creation theory.
E. Volcanic craters are formed by the explosion of compressed volcanic gases, which blasts out large volumes of fragments.
F. The application of field studies of the Meteor Crater to the formation of the Moon's Copernicus Crater effectively ended the centuries-old debate over the origin of lunar craters.
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