To address the plastic pollution troubling the world’s seas and waterways, Cornell University chemists have developed a new polymer (聚合物) that can degrade (降解) plastic when exposed to ultraviolet radiation, according to the research published in the Journal of the American Chemical Society.
“We have created a new plastic that has the mechanical properties required by commercial fishing gear. If it eventually gets lost in the water environment, this material can degrade on a realistic time scale,” said lead researcher Bryce Lipinski, professor of chemistry and chemical biology at Cornell University. “This material could effectively reduce persistent plastic accumulation in the environment.”
Commercial fishing contributes to about half of all floating plastic waste that ends up in the oceans. Fishing nets and ropes are primarily made from three kinds of polymers, none of which easily degrade. “While research of degradable plastics has received much attention in recent years,” Lipinski said, “obtaining a material with a mechanical strength comparable to commercial plastic remains a difficult challenge.”
Coates and his research team have spent the past 15 years developing the new plastic called isotactic polypropylene oxide, or iPPO. While its original discovery was in 1949, the mechanical strength of this material was unknown before this recent work. The high isotacticity and polymer chain length of their material makes it different from previous plastics and provides its mechanical strength.
Lipinski and other scientists want no race of the polymer to be left in the environment. He notes there is precedent (先例) for the biodegradation of small chains of iPPO which could effectively make it disappear and ongoing efforts aim to prove this.
1.What is the feature about the new polymer?
A.It can solve the problem of plastic consumption.
B.It can degrade plastic waste in the sea water.
C.It has been developed to solve plastic pollution.
D.It has been developed to lower fishing costs.
2.What can we infer from paragraph 3?
A.It requires great effort to invent the new plastic.
B.Fishing should be forbidden in the sea.
C.Fishing nets and ropes are not the major pollution source.
D.Degradable plastics were not paid attention to until recent years.
3.What did the recent study find about iPPO?
A.Its original discovery. B.Its mechanical properties.
C.Its complex structure. D.Its mechanical strength.
4.What is Lipinski’s attitude towards the future of iPPO?
A.Doubtful. B.Promising.
C.Unconcerned. D.Disapproval.
A couple John and Mary had a nice family and two lovely children. John had just been asked to go on a business trip to another city and would be gone for several days. It was decided that Mary needed an outing and would go along too. They hired a reliable woman to care for the children and made the trip, returning home a little earlier than they had planned.
As they drove into their home town happily, they noticed smoke, and they went off their usual route to see what it was. They found a home in flames. Mary said, “Oh well it isn’t our fire, let’s go home.” But John drove closer and exclaimed, “That home belongs to Fred Jones who works at the plant. He wouldn’t be off work yet, maybe there is something we could do.” “It has nothing to do with us.” protested Mary. “You have your good clothes on, let’s not get any closer.” But John drove up and stopped and they were both horror stricken to see the whole house in flames. A woman on the lawn was in hysterics screaming, “The children! Get the children!” sobbed the woman, “down the hall and to the left, they are in the basement.”
In spite of Mary’s protests John grabbed the water hose and soaked his clothes, put his wet handkerchief on his head and bolted for the basement full of smoke and scorching hot. He found the door and grabbed two children, holding one under each arm. As he left, he could hear some more whimpering. He delivered the two badly frightened and nearly suffocated children into waiting arms and filled his lungs with fresh air and started back asking how many more children were down there. They told him two more and Mary grabbed his arm and screamed, “John! Don’t go back! It’s suicide! That house will cave in any second!”
But he shook her off and went back. It seemed an eternity before he found the two children. As he stumbled up the endless steps, the thought went through his mind that there was something strangely familiar about the little bodies clinging to him, and at last when they came out into the sunlight and fresh air, he found that he had just rescued his own children.
The baby-sitter had left them at this home while she did some shopping.
1.What did the couple find first when they went back?
A.Their home caught fire. B.Fred John’s home caught fire.
C.The baby-sitter’s leaving. D.The woman’s screaming.
2.Why was Mary against John’s rescue at the beginning?
A.Because it’s none of their business. B.Because she was eager to see her children.
C.Because it would burn his good clothes. D.Because Fred didn’t work at the plant.
3.Which of the following can best describe John?
A.Warm-hearted and brave. B.Clumsy but cautious.
C.Generous and humourous. D.Determined but sensitive
4.What can we learn from the text?
A.Helping others is a god virtue. B.A good act will be well rewarded.
C.Misfortune tastes the sincerity of friends. D.Roses given to others, fragrance left in your hand.
The driver, Zhang Sai, hovered outside an apartment building in Wuhan, the central Chinese city at the heart of the coronavirus outbreak. He had been ordered not to take food to customers’ doors in order to minimize the risk of infection. But the woman on the phone was pleading, he recalled. The food was for her mother, who couldn’t go down to meet him. Mr. Zhang relented. He would drop off the order and sprint away. As he placed the bag on the floor, Mr. Zhang said, the door opened. Startled, he rushed away. Without thinking, he jabbed the elevator button with his finger, touching a surface that could transmit the virus. That was how Mr. Zhang, 32, found himself speeding back to his delivery station with one finger held aloft, careful not to touch the rest of his hand.
For many in China, delivery drivers like Mr. Zhang are the only connection to the outside world. Once a common but invisible presence on the streets of nearly every Chinese city, the drivers are now being honored as heroes. What exhausting and dangerous work! Mr. Zhang, who works for Hema, a supermarket chain owned by the tech giant Alibaba, crisscrosses (穿梭) the city armed only with the face masks and hand sanitizer that his company supplies each morning.
The epidemic has brought some unexpected bright spots. Before, Mr. Zhang said, he sometimes ran red lights during rush hour in order to meet his delivery goals for the day. Now, the streets are empty. He has no problem getting around. People are nicer, too. Some customers barely opened the door or avoided eye contact. After the outbreak erupted, everyone said thank you.
1.Why Zhang Sai couldn’t send food to customers’ doors?
A.To keep away from the deadly disease.
B.To reduce the chance of being transmitted.
C.To avoid communicating with others.
D.To give himself a day off.
2.What does the underlined word “relented” in paragraph 1 refer to?
A.promised B.denied
C.admitted D.refused
3.What advantages did the epidemic bring accidently?
A.Economic prosperity and long culture.
B.Busy business and peaceful people.
C.Splendid surroundings and energetic persons.
D.Empty streets and friendly people.
4.What can be the best title for the text?
A.The biography of Zhang Sai’s.
B.How did Zhang Sai send food?
C.The driver Zhang Sai during the epidemic.
D.How was Zhang Sai infected?
Animals in Odd Places
Tree Goats
These goats will do a lot for their favorite snacks-including climbing to the top of a 9-m-tall tree! Every summer the argan trees in southwest Morocco produce bitter-tasting fruit that the local goats can’t resist. And these peckish goats are doing us humans a favour — when they spit (for sometimes poo!) out the indigestible nut inside the argan fruit, the nuts can be collected to make an oil that’s used in hair products and food!
City Whales
They’re not visiting the Empire State Building — they’re on the lookout for food! Humpback whales are swimming back in the waters off the coast of New York City in the USA. Why? Years of cleanup efforts in the Hudson River — a tidal estuary where fresh and salt water meet — have brought back algae, zooplankton and fish. And the humpbacks, which are the ultimate foodie tourists, weren’t far behind! So far this year there have been an incredible 377 sightings.
Forest Penguins
Fiordland crested penguins prefer the warm waters and misty rainforest of southwest New Zealand to the icy Antarctic! With smaller bodies than many cold-weather penguins (such as emperors), the flightless birds live in balmy 21℃. And their eggs stay toasty in this warmer habitat, too, tucked away in caves, bushes and tree stumps where males sit on the nests.
Ocean Sloths
Pygmy three-toed sloths might be slow climbers, but when they get into the water, they’re powerful paddlers! These special sloths, which only live in the mangroves of a tiny island off the coast of Panama in Central America, plop into the sea when they want to move to a new tree. Their tummies are often filled with gas due to their leafy diet, so they stay afloat easily-and they can move three times faster in the water than they can on the ground. But since we’re talking about sloths, that’s really saying much!
1.What’s the function of Tree Goats’ poo?
A.It can improve human’s skin. B.It can be used as an oil.
C.It can be beneficial to our hair and food. D.It can be used as shampoo.
2.What’s the purpose of Humpback whales’ returning?
A.To visit the Empire State Building.
B.To look for food.
C.To clean up the Hudson River.
D.To search for fresh and salt water.
3.Which animals can move much faster in the water than on land?
A.Tree Goats B.City Whales
C.Forest Penguins D.Ocean Sloths
阅读下面材料，根据其内容和所给段落开头语写两段，使之构成一篇完整的短文。续写的词数应为150左右。
There was once a wonderful old man who loved everything: animals, spiders, insects and allsorts of living things.
One day while walking through the woods, the old man found a cocoon(茧) . He decided to take the cocoon home to watch its beautiful transformation from a little cocoon to a beautiful butterfly.
A few days later, the cocoon started to move. It moved frantically! He sat and watched it struggle and struggle for several hours. But it seemed not to make any progress. Then the old man felt sorry for the little butterfly inside, and rushed to its aid. With a pair of scissors and gently, he cut a little opening in the cocoon so the butterfly could come out. And then the butterfly came out of its cocoon. It had a swollen body and small, fragile wings, but it never was able to fly.
He was quite puzzled. Had he accidentally killed the little butterfly? No, it was still moving a little bit. Maybe it was sick. Then he decided that the best thing he could do for the butterfly was to place it gently back into its cocoon. He did so, and placed a drop of honey on it to seal the cocoon, leaving the butterfly to nestle (筑巢) in its natural state.
The next day he noticed that the cocoon was moving again. It struggled and struggled. Finally the butterfly broke free from its cocoon and stretched its wings out. Its beautiful wings were filled with wonderful colors! It took off! It was flying!
The wonderful butterfly flew and flew till it was almost out of the old man’ s sight. What a joy, he exclaimed! But then he started to think: what did I do wrong by trying to help that beautiful little butterfly out at first?
Finally the answer came out.
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Sometimes struggles are exactly what we need in our life.
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假定你是李华。你的外籍教师John本打算春季开学时返回中国，现因新冠（COVID－19）疫情待在London家中。你在英语学习中遇到了一些困难，请给他写一封email寻求帮助。内容如下：
1.询问John的健康情况；
2.告知学习中的困难；
3.请求帮助。
注意：1.词数80左右；
2.可以适当增加细节，以使行文连贯；
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