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2026年3月托福机经套卷(第2套)Read an Academic Passage5 道题

The Mystery of Dark Galaxies

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The Mystery of Dark Galaxies Ultraviolet (UV) astronomy has unveiled numerous cosmic phenomena. An especially intriguing discovery is that of dark galaxies. Unlike typical galaxies (gravitationally bound systems of stars, gas, and other particles), dark galaxies emit little to no visible light, making them nearly impossible to detect using conventional optical telescopes. However, these galaxies emit UV radiation, providing astronomers with a unique window to study them. █ Dark galaxies challenge our understanding of galaxy formation. █ Traditional models suggest that galaxies form through gas accumulation and star formation. █ But although dark galaxies contain vast amounts of gas, they have few, if any, stars. █ This raises questions about the processes that inhibit star formation. Some researchers propose that turbulence within the gas clouds might prevent the gas from collapsing to form stars. Observations from the Hubble Space Telescope and other UV-sensitive instruments have revealed that dark galaxies were more common in the early universe. These findings suggest that dark galaxies may represent a primordial phase in galaxy evolution. One hypothesis is that high levels of UV radiation in the early universe prevented the gas in dark galaxies from cooling and condensing into stars. Observations of regions with high UV radiation support this theory.
Question 1查看单题
The passage suggests that astronomers discovered dark galaxies by
Astudying numerous cosmic phenomena caused by them
Bobserving their gravitational effects on other galaxies
Cseeing them through conventional optical telescopes
Ddetecting UV radiation emitted by them
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正确答案:D
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Question 2查看单题
What might prevent the formation of stars in dark galaxies?
AThe accumulation of too much gas
BThe turbulence inside gas clouds
CThe presence of nearby galaxies
DThe collapse of gas clouds
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正确答案:B
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Question 3查看单题
Observations from the Hubble Space Telescope and other UV-sensitive instruments indicate that
Athe number of dark galaxies in the universe increased over time
Bdark galaxies contain more gas than previously believed
Cdark galaxies emit more UV radiation than previously believed
Ddark galaxies represent an early stage in galaxy development
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正确答案:D
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Question 4查看单题
Observations of dark-galaxy regions with high UV radiation indicate that
Adark galaxies evolved very slowly
Bstars in the early universe were fairly cool and dense
CUV radiation in the early universe kept gas temperatures high
Da traditional theory of how dark galaxies formed is incorrect
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正确答案:C
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Question 5查看单题
There are four locations █ in the passage that indicate where the following sentence could be added.
Therefore, one might expect all galaxies to have a significant number of stars.
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