Giving silkworm silk a metallic bath may make the strands （絲線） both strong and solid，scientists reported on October 6 in Matter.The work is the latest in a decades-long pursuit of creating fibers as strong，lightweight and biodegradable as spider silk.If scientists can mass-produce such material，the potential uses will range from the biomedical to the athletic.Sewing （縫） up wounds，even sporting equipment could get a significant improvement.
"Hunting for enough silky material to make these super strong products has been a big barrier.Silk from silkworms is simple to harvest，but not all that strong.And spider silk，the gold-standard for hand-spun strength and toughness，is not exactly easy to collect.Unlike silkworms，spiders cannot be farmed due to their nature，" wrote study coauthor Zhi Lin，a structural biologist at Tianjin University.
"Scientists around the world have tried to spin （編織） strong strands in the lab using silkworm cocoons.The first step is to take off the silk's sticky outer coating.Scientists can do this by boiling the fibers in a chemical bath，but that can be like taking a knife to silk proteins.If the proteins get too damaged，it's hard for scientists to respin them into high-quality strands，" said Chris Holland，a materials scientist at the University of Sheffield.
Lin's team tried gentler approaches，one of which used lower temperatures and a papaya enzyme （木瓜酵素），to help dissolve （溶解） the silk's coating.That seemed to work.They don't have little pieces of silk protein.That's huge because the bigger the proteins that remain，the stronger the fibers are going to be.After some processing steps，the researchers bathed the pressed silk in a solution containing zinc and iron ions （鋅鐵離子）.That was why some of the strands were so strong — Lin's team detected zinc ions in the finished fibers.
But Holland wasn't so sure. "The team's real innovation may be that they've managed to untwist silk in a less damaging way.The silk protein remains in a good state，" he said， "In my mind，that's a major step forward."
（1）Why is creating super strong silk worth the long-time pursuit？ CC
A．It can be mass-produced.
B．It promotes athletic training.
C．It might have wide applications.
D．It is potentially environmentally friendly.
（2）What makes it hard to collect desirable natural silk according to Lin？ DD
A．The poor harvest of silkworm silk.
B．The low quality of spider silk.
C．The absence of silkworm data.
D．The insufficient supply of spider silk.
（3）How did Lin's team make the silk fiber strong？ BB
A．By enhancing its protein.
B．By bathing it in metallic liquid.
C．By removing its coating.
D．By squeezing it firmly in a tube.
（4）In what aspect did Lin's team make a breakthrough according to Holland？ AA
A．Processing silk in a safer method.
B．Mass-producing silk.
C．Creating silk of superior quality.
D．Analyzing silk scientifically.
【答案】C；D；B；A
【解答】
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發(fā)布：2024/10/9 0:0:2組卷：4引用：4難度：0.5
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Protecting habitats（棲息地）is important for keeping biodiversity.In 2003，over 102，000 habitats covering nearly 19 million square kilometres，or 11.5% of the world's land surface，were under some form of protection.Though this is a great improvement since 1962，when just 1，000 protected habitats were listed，it is still not considered enough to stop the ecocide that is endangering the world's biodiversity.
For a number of environmentalist，protecting the world's 25 biodiversity hotspots（熱點(diǎn)地區(qū)）is critical to saving habitats and species.But many hotspots are endangered already，having lost up to three-quarters of their original plants.
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Protecting hotspots is not simply a matter of putting up fences and employing guards.The best results are achieved when local people are educated about the value of wildlife，and actually gain a share of the benefits from eco-tourism.Only then do they have a chance to see the benefits of protecting hotpots.
（1）What can we infer from paragraph 1？
A．The loss of any species can affect humans.
B．Endangered species are paid more attention to by humans.
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D．Ecosystem protection is as important as diversity protection.
（2）What does the underlined word "ecocide" in paragraph 2 mean？
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B．Reduction of the number of species.
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D．Habitats protection.
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A．Population growth in hotpots.
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（4）What's the author's opinion on protecting the hotspots？
A．It's simple to carry out.
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We need the wild world.It is essential to our wellbeing，our health and our happiness.
（1）According to the author，people enjoyto seek nature.
A．jogging on the street
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D．sitting in the garden
（2）From the second paragraph，we can see that.
A．Children don't want to approach nature
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B．Children's performance at school is greatly improved.
C．Problems with crime and violent behavior will easily be solved.
D．A garden nearby improves the quality of old people's life.
（4）what is the main idea of this passage？
A．Access to nature improves our life.
B．Nature treats children for ADHD.
C．Getting close to nature reduces crime.
D．Man can't live without natural areas.發(fā)布：2025/1/6 16:30:6組卷：0引用：1難度：0.5 -
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Inclusive Minds，a group that is working to make children's literature more inclusive and accessible，reviewed the language in a partnership effort with Puffin Books.Inclusive language avoids terms that could be seen as excluding specific groups of people.Any changes were"small and carefully considered，"the company said.
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