14.MANY of us remember being in awe (敬畏) when we saw cloned dinosaurs (恐龙) running wild in the film Jurassic Park.And the idea of using technology to revive (恢复) extinct species has long fascinated not only writers and directors,but scientists as well.
According to The Telegraph,woolly mammoths (长毛猛犸象),which featured in the popular Ice Age animated movie series,"may walk the earth once more"now that scientists have taken another step toward realizing a long-held dream-recreating their DNA.?
Mammoths became extinct around 10,000 years ago.However,since the discovery of near-perfect preserved remains in Arctic permafrost (北极冻土带) in May 2013,a variety of research studies have been carried out since.
Geneticists from Harvard University analyzed DNA from the remains,looking for genes which separated mammoths from elephants,such as hairiness and ear size.They then used the results to reproduce exact copies of 14mammoth genes."It is the first time that mammoth genes have been alive-although so far it has only been done in the lab,"George Church,lead researcher of the project,told the Sunday Times.
Church then used a new technique which allows scientists to edit DNA carefully,replacing sections of elephant DNA with the mammoth genes.So"we now have functioning (正常运行的) elephant cells with mammoth DNA in them,"he said.
However,Church ruled out the possibility of bringing the mammoths back to life via cloning from frozen remains.He said he"preferred to focus on rebuilding the full mammoth genome by analyzing DNA from preserved remains and putting it into the cells of its closest living relative-the Asian elephant,"reported The Telegraph.?
Church argued that the return of the woolly mammoth-or rather,the return of something very similar-could help bring back fragile (脆弱的) ecosystems.However,some scientists believe that bringing back the mammoth would be unethical.
Professor Alex Greenwood,an expert on ancient DNA,said:"We may face the extinction of African and Asian elephants.Why bring back another elephant from extinction when we cannot even keep the ones that are not extinct around?"he told the Sunday Times."What is the message?We can be as irresponsible with the environment as we want.Then we'll just clone things back?"
"Money would be better spent focusing on conserving (保护) what we do have than spending it on an animal that has been extinct for thousands of years,"he said.

61.We can infer from the article thatC.
A.scientific studies on mammoths didn't begin until May 2013
B.the technology to revive mammoth genes is already mature
C.George Church and his colleagues tried to reproduce mammoth DNA
D.Church and his team managed to list all the genes that separate mammoths from elephants
62.According to Church,what is the significance of his study?C
A.It could help prevent the extinction of the Asian elephant.
B.It could help people better tell elephant DNA from mammoth genes.
C.It could help bring back some extinct species and save fragile ecosystems.
D.It could help bring mammoths back to life via cloning from frozen remains.
63.The underlined word"unethical"in Paragraph 7 is closest in meaning toA.
A.wrong 
B.essential
C.impractical 
D.interesting
64.According to the article,Professor Alex Greenwood believes thatD.
A.there is no need to worry about the extinction of African and Asian elephants at present
B.it's necessary to bring back species that are beneficial to human beings from extinction
C.the return of the woolly mammoth would help to balance ecosystems
D.it's more important to protect present species than to bring back extinct ones.
7.Cutting trees in half can help scientists understand the past and now it appears it can be used to predict the future.Researchers have been looking at ring growth from trees to make sense of past weather patterns such as droughts and rain.
    Combining data from the rings allowed them to create a copy of pictures of climate changes over the past 2,000 years and this information could also be used to foresee future famine(饥荒),unrest and conflict.The project has been named Old World Drought Atlas,or OWDA.
     Its main author,Columbia biologist Edward Cook,has already carried out similar projects using trees to create chronological(按顺序排列的) maps of drought  in Asia and North-America.He believes that combining the three atlases could throw light on the global causes of drought and climate change.
     The study,for instance,gave special attention to the importance of one of such causes,the North Atlantic Oscillation(涛动),in affecting climate patterns in Europe,and specifically in making Europe wetter north of the Alps and drier south of them.
     The OWDA also helped analyse historical events from a climatic perspective.For  instance,the 1740-174l famine in Ireland had so far been explained by an unusually cold winter and spring,but the atlas shows that unusually low rainfall over the spring and summer of 1741 could also have played a role.Finally this made growing food nearly impossible and caused a continent-wide famine.
      A better grasp of these processes could even make it possible to predict future  famine,unrest and conflict.
      Cook said,64The Old World Drought Atlas fills a major geographic gap in the data that's important to determine patterns of climate changes in time.That's important for understanding causes of many droughts,and it's important for climate modelers to test hypotheses(偎说)  of climate forcing and change.
  
32.Why is ring growth useful in research?B
A.It's the best way to understand the past.
B.It could be used to predict the future.
C.It could be used to prevent the outbreak of droughts and rain.
D.It isn't mentioned in the passage.
33.People worldwide can read chronological maps of droughtA.
A.in Asia
B.in Africa
C.in Europe
D.in South America
34.What is the author's attitude toward the study of OWDA?C
A.Positive.
B.Negative.
C.Objective.
D.Conservative.
35.Why did the author of the passage mention what Cook said?B
A.To show he interviewed Cook himself.
B.To tell us the importance of OWDA.
C.To compare climate variability.
D.To analyse how to predict droughts.
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