题目：
Planetary scientists have struggled to understand how three rocky planets could have turned out so differently. Why is the atmosphere on Venus 100 times as dense as Earth’s, which is in turn 100 times denser than the air on Mars? During the early stages of planetary formation, all three embryonic worlds were probably very similar, their growing cores all gathering dust and asteroids (large rocks that circle the Sun) from those swirling around our young Sun. But Earth and Venus, being farther away from the gravitational pull of Jupiter, began to grow bigger than Mars. As the planets grew, their gravitational pull got stronger and the asteroids and lumps of dust rained down at higher and higher speeds until they were partially vaporized (turned into gas) on impact, probably along with a fair proportion of the planets’ surface. These impacting objects were predominantly a mixture of rock and water ice. At first, the steam released on impact would drift off into space. But as the planets swelled in size, so did their gravitational pull, and eventually the gas could not escape. Soon the developing Earth and Venus were surrounded by a thick layer of hot steam. At a temperature of around 1,500 degrees centigrade, these were the first atmospheres of the inner solar system.
By this stage, Mars had already gone down a different path. With only one-tenth the mass of Earth or Venus, Mars never managed to cause impacting asteroids to bombard it fast enough for them to be vaporized. Early Mars would have had a small amount of steam and some other gases in its thin air, and we know it must have had water on its surface, but most of the volatile chemicals were still in the form of underground ice. As the red planet cooled, much of its early atmosphere ended up as a layer of frost trapped in the surface.
The thinner an atmosphere is to start with, the harder it is to keep hold of. The early solar system contained a large family of asteroids left over after the planets finished forming, and during the following half billion years there were plenty of catastrophic collisions between the planets and these floating mountains. These devastating impacts would blow huge sections of the planets’ atmospheres into space. Mars, with its weak gravity and already thin atmosphere, would have suffered from this loss much more than Earth and Venus.
There is much debate about the exact sequence of events on Earth and Venus during those first half billion years, but the current best guess seems to be that as the planets cooled down, some of the thick veil of steam rained out onto the surface as reservoirs of water. This certainly happened on Earth. On Venus, closer to the Sun and always hotter than Earth, if there ever were oceans, they would never have cooled much below boiling point. The atmosphere on Venus was continually saturated with steam. That was the critical difference that divided the destinies of these two planets.
Water vapor is the most efficient greenhouse gas known to science. It is transparent to visible light but reflects infrared light. As the Sun’s rays fell on the young and steamy Venus, a small amount penetrated the fog and reached the surface, where it was absorbed. Hot rocks then radiated the Sun’s energy back into the atmosphere in the form of infrared heat, which was completely sealed in by the thick veil of water. Venus stayed hot.
Meanwhile, high up in the atmosphere of Venus, ultraviolet light from the Sun was breaking water into its chemical constituents, hydrogen and oxygen.Hydrogen is so light that, once released from the heavier atoms of oxygen, it simply floats off into space. Some of the oxygen would have been knocked out by the escaping hydrogen atoms, but most would join with carbon atoms in the hot surface rocks to form carbon dioxide, another potent greenhouse gas.Thus, although the oceans gradually boiled away into the sky and that shroud of steam slowly disappeared, the greenhouse effect never stopped.Steam in the atmosphere of Venus was slowly replaced with the massive amount of carbon dioxide that we see today.
1
Planetary scientists have struggled to understand how three rocky planets could have turned out so differently. Why is the atmosphere on Venus 100 times as dense as Earth’s, which is in turn 100 times denser than the air on Mars? During the early stages of planetary formation, all three embryonic worlds were probably very similar, their growing cores all gathering dust and asteroids (large rocks that circle the Sun) from those swirling around our young Sun. But Earth and Venus, being farther away from the gravitational pull of Jupiter, began to grow bigger than Mars. As the planets grew, their gravitational pull got stronger and the asteroids and lumps of dust rained down at higher and higher speeds until they were partially vaporized (turned into gas) on impact, probably along with a fair proportion of the planets’ surface. These impacting objects were predominantly a mixture of rock and water ice. At first, the steam released on impact would drift off into space. But as the planets swelled in size, so did their gravitational pull, and eventually the gas could not escape. Soon the developing Earth and Venus were surrounded by a thick layer of hot steam. At a temperature of around 1,500 degrees centigrade, these were the first atmospheres of the inner solar system.
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.
Sentence Simplification Questions句子简化题
AThe growing planets eventually pulled objects at such high speeds that the objects and probably the planets’ surfaces partially vaporized on impact.
BThe planets grew more and more rapidly, with their surfaces consisting partially of dust, which had rained down together with asteroids, and gas.
CAs the planets grew in size, asteroids and lumps of dust flew towards them at higher and higher speeds, often vaporizing before they reached the planets’ surface.
DThe planets grew quickly despite asteroid impacts that vaporized a fair proportion of their surfaces.
2
Planetary scientists have struggled to understand how three rocky planets could have turned out so differently. Why is the atmosphere on Venus 100 times as dense as Earth’s, which is in turn 100 times denser than the air on Mars? During the early stages of planetary formation, all three embryonic worlds were probably very similar, their growing cores all gathering dust and asteroids (large rocks that circle the Sun) from those swirling around our young Sun. But Earth and Venus, being farther away from the gravitational pull of Jupiter, began to grow bigger than Mars. As the planets grew, their gravitational pull got stronger and the asteroids and lumps of dust rained down at higher and higher speeds until they were partially vaporized (turned into gas) on impact, probably along with a fair proportion of the planets’ surface. These impacting objects were predominantly a mixture of rock and water ice. At first, the steam released on impact would drift off into space. But as the planets swelled in size, so did their gravitational pull, and eventually the gas could not escape. Soon the developing Earth and Venus were surrounded by a thick layer of hot steam. At a temperature of around 1,500 degrees centigrade, these were the first atmospheres of the inner solar system.
The word “predominantly” in the passage is closest in meaning to
Vocabulary Questions词汇题
Amainly
Binitially
Cusually
Dprobably
3
Planetary scientists have struggled to understand how three rocky planets could have turned out so differently. Why is the atmosphere on Venus 100 times as dense as Earth’s, which is in turn 100 times denser than the air on Mars? During the early stages of planetary formation, all three embryonic worlds were probably very similar, their growing cores all gathering dust and asteroids (large rocks that circle the Sun) from those swirling around our young Sun. But Earth and Venus, being farther away from the gravitational pull of Jupiter, began to grow bigger than Mars. As the planets grew, their gravitational pull got stronger and the asteroids and lumps of dust rained down at higher and higher speeds until they were partially vaporized (turned into gas) on impact, probably along with a fair proportion of the planets’ surface. These impacting objects were predominantly a mixture of rock and water ice. At first, the steam released on impact would drift off into space. But as the planets swelled in size, so did their gravitational pull, and eventually the gas could not escape. Soon the developing Earth and Venus were surrounded by a thick layer of hot steam. At a temperature of around 1,500 degrees centigrade, these were the first atmospheres of the inner solar system.
It can be inferred from paragraph 1 that Mars ended up being smaller than Earth and Venus because
Inference Questions推理题
AVenus and Earth started with denser cores
BMars experienced more asteroid impacts, which broke it apart
CVenus and Earth were closer to the dust and asteroids swirling around the Sun
DMars’s nearness to Jupiter limited its growth
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Planetary scientists have struggled to understand how three rocky planets could have turned out so differently. Why is the atmosphere on Venus 100 times as dense as Earth’s, which is in turn 100 times denser than the air on Mars? During the early stages of planetary formation, all three embryonic worlds were probably very similar, their growing cores all gathering dust and asteroids (large rocks that circle the Sun) from those swirling around our young Sun. But Earth and Venus, being farther away from the gravitational pull of Jupiter, began to grow bigger than Mars. As the planets grew, their gravitational pull got stronger and the asteroids and lumps of dust rained down at higher and higher speeds until they were partially vaporized (turned into gas) on impact, probably along with a fair proportion of the planets’ surface. These impacting objects were predominantly a mixture of rock and water ice. At first, the steam released on impact would drift off into space. But as the planets swelled in size, so did their gravitational pull, and eventually the gas could not escape. Soon the developing Earth and Venus were surrounded by a thick layer of hot steam. At a temperature of around 1,500 degrees centigrade, these were the first atmospheres of the inner solar system.
According to paragraph 1, which of the following is NOT true of the first atmospheres on Earth and Venus?
Negative Factual Information Questions否定事实信息题
AThey were around 1.500 degrees centigrade
BThey were composed mainly of steam.
CThey were created by asteroid impacts.
DThey drifted off into space as the planets grew.
5
By this stage, Mars had already gone down a different path. With only one-tenth the mass of Earth or Venus, Mars never managed to cause impacting asteroids to bombard it fast enough for them to be vaporized. Early Mars would have had a small amount of steam and some other gases in its thin air, and we know it must have had water on its surface, but most of the volatile chemicals were still in the form of underground ice. As the red planet cooled, much of its early atmosphere ended up as a layer of frost trapped in the surface.
According to paragraph 2. what are TWO reasons that Mars’s early atmosphere was thinner than the atmospheres of Earth and Venus?To receive credit, you must select TWO answers
Factual Information Questions事实信息题
Select 2 answers
AMore of Mars’s gases and chemicals were volatile.
BMars cooled more quickly because of its smaller mass.
CMost of Mars’s volatile chemicals were frozen
DThe asteroids that bombarded Mars were not vaporized
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The thinner an atmosphere is to start with, the harder it is to keep hold of. The early solar system contained a large family of asteroids left over after the planets finished forming, and during the following half billion years there were plenty of catastrophic collisions between the planets and these floating mountains. These devastating impacts would blow huge sections of the planets’ atmospheres into space. Mars, with its weak gravity and already thin atmosphere, would have suffered from this loss much more than Earth and Venus.
According to paragraph 3, why did Mars lose more of its atmosphere to asteroid impacts than Earth or Venus lost?
Factual Information Questions事实信息题
AMars was closest to a part of the solar system that contained a family of the largest asteroids, and thus it suffered the largest impacts
BUnlike Earth and Venus, Mars had already had collisions with other planets before the asteroid impacts began.
CMars had a thinner atmosphere than those of the other planets before the impacts began.
DMars experienced a higher number of asteroid collisions during its early history than the other planets did.
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There is much debate about the exact sequence of events on Earth and Venus during those first half billion years, but the current best guess seems to be that as the planets cooled down, some of the thick veil of steam rained out onto the surface as reservoirs of water. This certainly happened on Earth. On Venus, closer to the Sun and always hotter than Earth, if there ever were oceans, they would never have cooled much below boiling point. The atmosphere on Venus was continually saturated with steam. That was the critical difference that divided the destinies of these two planets.
It can be inferred from paragraph 4 that scientists are not entirely certain about
Inference Questions推理题
Awhether Venus ever had a significant amount of liquid surface water
Bwhy Venus remained so much hotter than Earth
Chow much Earth was cooled by its reservoirs of water
Dwhether Venus had periods with no steam in its atmosphere
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Water vapor is the most efficient greenhouse gas known to science. It is transparent to visible light but reflects infrared light. As the Sun’s rays fell on the young and steamy Venus, a small amount penetrated the fog and reached the surface, where it was absorbed. Hot rocks then radiated the Sun’s energy back into the atmosphere in the form of infrared heat, which was completely sealed in by the thick veil of water. Venus stayed hot.
Why does the author provide the information that “Water vapor is the most efficient greenhouse gas known to science”?
Rhetorical Purpose Questions修辞目的题
ATo explain why only a small amount of the Sun’s visible light was able to reach the surface of Venus
BTo explain why Venus remained extremely hot
CTo make a connection between processes that occurred on early Venus and processes that occur on Earth today
DTo provide evidence that early Venus was covered in fog
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Meanwhile, high up in the atmosphere of Venus, ultraviolet light from the Sun was breaking water into its chemical constituents, hydrogen and oxygen. ⬛Hydrogen is so light that, once released from the heavier atoms of oxygen, it simply floats off into space. ⬛Some of the oxygen would have been knocked out by the escaping hydrogen atoms, but most would join with carbon atoms in the hot surface rocks to form carbon dioxide, another potent greenhouse gas.⬛Thus, although the oceans gradually boiled away into the sky and that shroud of steam slowly disappeared, the greenhouse effect never stopped.⬛Steam in the atmosphere of Venus was slowly replaced with the massive amount of carbon dioxide that we see today.
Look at the four squares ⬛ that indicate where the following sentence could be added to the passage
Although they are all rocky planets, Earth, Venus, and Mars have very different atmospheres.Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
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Although they are all rocky planets, Earth, Venus, and Mars have very different atmospheres.
Prose Summary Questions概要小结题
Select 3 answers
AThe force of Jupiter’s gravity pulled steam and other gases away from the atmosphere of Mars, resulting in a loss of atmosphere.
BUnlike Earth and Venus, Mars never got big enough to cause steroids to vaporize on impact, so its atmosphere started out thin and became even thinner
CVenus’s steamy atmosphere kept the planet very hot, and the carbon dioxide that replaced its water vapor had a similar greenhouse effect.
DBecause it was smaller than the other planets to begin with, Mars did not suffer the types of asteroid impacts that caused large pieces of Earth and Venus to be blown off into space.
EWhile water in Earth’s atmosphere definitely formed oceans as the planet cooled, the atmosphere of Venus, a hotter planet, continued to hold much of its water vapor.
FUltraviolet light from the Sun slowly increased the oxygen in Earth’s atmosphere while reducing the amount of carbon dioxide.
