Earthquakes have rocked the planet for many years.Studying the quakes of the past could help scientists better understand modern earthquakes，but tools to do such work are exiguous.
Enter zircons.Researchers used this special means to home in on the temperatures within a fault （地殼斷層） during earthquakes millions of years ago.The method offers insights into the strength of long-ago quakes，and can improve the understanding of how today's earthquakes release energy，the researchers reported in the April Geochemistry，Geophysics，Geosystems.
"The more we understand about the past，the more we can understand what might happen in the future，" said Emma Armstrong，a professor specializing in earthquakes at Utah State University in Logan.Armstrong and his colleagues focused on California's Punchbowl Fault.That now-quiet portion of the larger San Andreas Fault was probably active between 1 million to 10 million years ago，Armstrong said.
Heat from friction （摩擦） is generated in a fault when it slips and touches off an earthquake.Previous analyses of preserved organic material suggested that temperatures within the Punchbowl Fault peaked between 465℃ and 1065℃.The researchers suspected that zircons in rocks from the fault could narrow that broad window.Zircons often contain the radioactive chemical elements uranium （U） and thorium（Th），which decay （衰變） to helium （He） at a predictable rate.That helium （He） then builds up in the crystals.But when a zircon is heated past a temperature criticality value—the size of which depends on the zircon's composition—the accumulated helium （He） escapes.
Measuring the amounts of the three elements in zircons from the fault suggests that the most in-tense earthquake generated temperatures lower than 800℃.That roughly halves the range previously reported.The finding provides useful clues to the amount of heat released by quakes，something difficult to measure for modern earthquakes because they often occur at great depths.Armstrong plans to continue studying zircons，in the hope of finding more ways to take advantage of them for details about ancient quakes.
（1）What does the underlined word "exiguous" in Paragraph 1 mean？ AA
A．Scarce.
B．Difficult.
C．Pricey.
D．Extraordinary.
（2）What are the researcher's assumptions about the zircons in rocks？ CC
A．They can lead to various earthquakes.
B．They determine how much of their energy.
C．They can reduce the fault temperature range.
D．They would decay over long periods.
（3）What might Emma Armstrong study next？ DD
A．Impact of changing earthquakes on zircons.
B．Origin and development of enter zircons.
C．Difference between modern and ancient quakes.
D．More ways to use zircons for ancient quake study.
（4）Which of the following can be the best title for the text？ BB
A．Earthquakes Bring about Global W arming
B．Ancient Zircons Help to Unearth Earthquakes
C．An Innovative Means Makes a Hit in Studying
D．Zircons Changed Our Views of Earthquakes
【考點】自然生態(tài)與環(huán)境保護；說明文．
【答案】A；C；D；B
【解答】
【點評】
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發(fā)布：2024/5/27 14:0:0組卷：4引用：5難度：0.5
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Our school held an activity on last Sunday because it was "Earth Day".Hundred of students took part in it.I am one of them.First，the headmaster gave us a speech about how to protect earth—our home.Then we went hiking，this was about 15km.Although the hiking was very tired，none were left behind.It is no doubt that all of us like the activity.In the future，they will try hardly to protect the environment.We hope we will take part in more activity about caring about the globe.發(fā)布：2024/6/27 10:35:59組卷：0引用：1難度：0.5 -
2．Leading a sustainable （可持續(xù)的） lifestyle doesn't require you to have to make great changes to your home，and this kind of transformation doesn't have to be an exhausting exercise. （1）
Here are three of them.
（2）By using solar energy，you will make your home far more sustainable.Solong as there is the sun in the sky，the solar panels atop your house will catch the rays and then transform them into electricity.
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You have the power to make a sustainable change to your lifestyle—take the above advice and don't waste it.
A．Turn to solar energy.
B．Avoid wasting valuable resources.
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D．Two choices you have are sharing cars and taking public transport.
E．There're many easy and simple things you can do to be more sustainable.
F．Another change you can make in this instance is to stop using plastic straws.
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3．The Sixth Extinction（滅絕） Extinctions，where entire species are wiped out，are not unusual in our Earth's history.In fact，over 90 percent of all species that ever lived are now extjye.aict.In the last 500 million years，there have been five times when life on Earth has almost ended.These include the third mass extinction，known as the"Great Dying"，which killed 90% to 96% of all species.And the fifth event，which occurred 66 million years ago，caused the death of the dinosaurs.The reasons for extinctions are varied.According to scientists，they include volcanic eruptions，asteroids （小行星） hitting the Earth from space，changes in sea levels，the decrease of the oxygen content of the sea and global warming.Many scientists say we are now entering the Earth's sixth mass extinction.This time，human activity will be to blame.
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（1）What are the reasons for extinction in the history？
（2）Why does the writer believe we will probably die out if 3/4 of the Earth's species die out？
（3）Please decide which part is false in the following statement，then underline it and explain why.
It is not unusual for species to die out naturally，so we human beings are not to blame.
（4）What actions can we take to avoid the sixth extinction？ （In about 40 words）發(fā)布：2024/6/27 10:35:59組卷：3引用：1難度：0.5
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