1 . “Leaves on the line” is a troublesome term for rail operators.
When leaves fall on to a railway line, they form an extremely low-friction black paste. When compressed by a slowly moving train, the paste becomes sticky and prevents the wheel from touching the rail, leading to lengthy delays and extreme safety concerns.
Discovering why leaves pose such a problem has taken years of research.
Sycamore (梧桐树) leaves are known to create this slippery black substance. It reduces friction between wheel and rail to around 0.01 per cent — the same as between ice and a skate.
To find out what chemical in the leaves was responsible for the paste, the researchers used a process of elimination (排除过程). Different chemicals were removed but the paste still formed. However, when tannins (单宁酸) were removed, the paste did not form.
In plants, these large molecules are used to soak up disease and stop it spreading, as well as making the plants taste bitter in order to discourage animals from eating them. But when the leaves fall on to a railway line, these tannins react with charged iron particles from the steel rails to form an extremely low-friction black paste.
“With this chemical reaction found and linked to low friction phenomena, interventions (干预措施) can be designed,” researchers conclude. They say this discovery could help design policies to cut down problem trees. For example, instead of removing all trees near railway lines, it may be better to just cut down the species that contain tannins.
However, another solution may lie in stopping the tannins from the leaves interacting with the ions (离子) in the steel at all. “Interventions can be designed to target the specific reactions or chemicals,” the researchers say. At present they are still working on it.
1. What’s the problem with leaves on the line?| A．They do harm to the environment. |
| B．It' s hard for rail operators to clean up them. |
| C．When pressed their chemical slows down the train. |
| D．They increase the friction between the train and railway. |
| A．cause. | B．absorb. | C．reduce. | D．increase. |
| A．Remove tannins from leaves. |
| B．Get rid of all trees near railway lines. |
| C．Change the position of railway lines to avoid leaves. |
| D．Prevent the chemical reactions between tannins and ions. |
| A．The troublesome leaves will cause danger to passengers. |
| B．The discovery of the chemical reaction helps design policies. |
| C．Tannins are responsible for the paste formed by compression. |
| D．Currently, researchers succeed in stopping the chemical reaction. |
2 . A new Northwestern University study reaffirms the importance of getting a good night’s sleep. By examining fruit flies’ brain activity and behavior, the researchers found that deep sleep has the power to clear waste from the brain. This waste potentially includes poisonous proteins that may lead to neurodegenerative (神经退化) diseases. “Waste clearance could be important, in general, for maintaining brain health or for preventing neurodegenerative diseases,” said Dr. Allada, senior author of the study. “Waste clearance may occur during wake and sleep but is greatly strengthened during deep sleep.”
Although fruit flies seem very different from humans, the neurons (神经元) that govern flies’ sleep-wake cycles are strikingly similar to our own. For this reason, fruit flies have become a well-studied model organism for sleep and neurodegenerative diseases.
In this current study, Allada and his team examined Proboscis (针状喙) Extension Sleep, a deep-sleep stage in fruit flies, which is similar to deep, slow-wave sleep in humans. The researchers discovered that, during this stage fruit flies repeatedly extend and move back their proboscises. “This kind of movement moves fluids possibly to the fly version of kidneys (肾),” Allada said. “Our study shows that this promotes waste clearance and aids in injury recovery.”
When Allada’s team disturbed flies’ deep sleep, the flies were less able to clear the waste from their systems and were more likely to be influenced by injuries.
Allada said this study brings us closer to understanding the mystery of why all organisms need sleep. All animals, especially those in the wild, are incredibly weak when they sleep, but research increasingly shows that the benefits of sleep, including crucial waste removal, are greater than this increased weakness.
1. How did the researchers draw the conclusion of their study?| A．By working out the result by chance. |
| B．By predicting the result from the old data. |
| C．By making observation and analysis. |
| D．By making a range of comparisons. |
| A．The disturbance of fruit flies’ deep sleep. |
| B．The governing of fruit flies’ sleep-wake cycles. |
| C．The moving of fluids to the fruit flies’ kidneys. |
| D．The extension and moving of fruit flies’ proboscises. |
| A．The fact that all organisms need sleep. |
| B．The application of the result of the study. |
| C．The disadvantages of the sleep of animals. |
| D．The great value of mankind’s and animals’ sleep. |
| A．Studies on Proboscis Extension Sleep |
| B．Deep Sleep Takes Out the Brain Trash |
| C．Different Functions of Waste Clearance |
| D．Similarities of Sleep-Wake Cycles Between Fruit Flies and Humans |
3 . One day, rain was falling. I saw an old, wet dog walking to my house. The leather collar around his neck was
The old dog
Every moment of love you create is a
| A．worn | B．tight | C．rare | D．delicate |
| A．superb | B．full | C．simple | D．ordinary |
| A．raced | B．failed | C．ached | D．danced |
| A．fetched | B．noticed | C．prepared | D．grabbed |
| A．eyed | B．kicked | C．nosed | D．attacked |
| A．jokingly | B．cheerfully | C．anxiously | D．gently |
| A．skipped | B．took | C．followed | D．tripped |
| A．waited | B．trembled | C．hesitated | D．shouted |
| A．meal | B．walk | C．bath | D．break |
| A．affected | B．adopted | C．injured | D．abandoned |
| A．skillfully | B．attentively | C．greedily | D．leisurely |
| A．awkward | B．curious | C．familiar | D．happy |
| A．rescue | B．protect | C．observe | D．reward |
| A．belief | B．prayer | C．promise | D．request |
| A．recreation | B．treasure | C．commitment | D．comfort |
My job is just one of the essential jobs, a sanitation（卫生系统）engineer, not a glamorous one, but is considered the alternative. Of course, I never regard it as an ashamed task to be in my position. About the second week of the lockdown because of the Covid-19, I was having trouble finding a sanitizing spray（消毒喷雾）for my truck. The next morning on my way to work at 4 a. m., I stopped at one of the few stores which were open that early, hoping to purchase some. However, it was only open for the police and medical personnel. “Look at my vest please,” I begged to the clerk, “I’m not just buying it for myself.” “I’m more than sorry, sir. But this is just the regulation, and I really can’t help.” replied the smiling girl. As I turned to head back to my car with disappointment, I nearly broke down.
Coming out of the store, my stomach began to call for energy support. I stopped at a 7/11 and ordered an everything bagel（硬面包）with cream cheese to satisfy my poor stomach and my empty heart. It was toasty warm, and I couldn’t wait to dig in. But as I left the store with a little joy coming sweetly from the bagel, I noticed a scene that an old man was sitting at the bus stop, in rags. Knowing that it would probably be his only warm meal of the day, I gave him the bagel without any hesitation. Just when I was ready to turn around for another same bagel, something warming my heart came into being. Another customer, a gentle lady, from the 7/11 offered me half of her bagel. “We everyone should be taken care of at some certain moment.” she said with a tender sweet voice as I smiled to thank her sincerely. I was delighted because I realized that in one way or another, we were all looked after.
注意：续写词数应为150左右。
So I decided to go back to the former store to try my luck again for the spray.
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Just before I gave up, a local policeman was heading into the store.
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The Shangsi Festival, also known as the Double Third Festival is 56.
The Shangsi Festival 58.
6 . Many people think daydreaming is bad for their emotions and has negative effects on their life and those around them. It makes adapting to life very hard and brains work less effectively.
Contrary to common ideas, the brains of people who are daydreaming might not stop working, but may be working harder, new research has shown. Scientists scanned the brains of people lying inside magnetic resonance imaging (MRI) machines, as they pushed buttons or rested in turn. The scans showed that the “default (默认的) network” deep inside a human brain becomes more active during daydreaming.
In a surprise finding, the scans also showed strong activity in the executive network, the outlying region of the brain associated with complex problem-solving, says Professor Kalina Christoff, who is a co-author of the study. “People assume that when the mind wanders away, it just gets turned off—but we show the opposite. When it wanders, it is turned on.” says Christoff.
The findings, published in Proceedings of the National Academy of Sciences, suggest, “People who let themselves daydream might not think in the same focused way as when performing a goal-oriented task, but they bring in more mental and brain resources,” says Christoff.
F. Diane Barth said at Psychology Today that the more we daydream, the more our brain is able to hold onto the task when we are being bombarded (轰炸) from all sides by all kinds of noises, information input, and conflicting demands. You're not trying to escape the task at hand; rather, you're trying to get rid of all of the information and stimuli (刺激物) that could pose as bothers.
According to Christoff, people typically spend one third of their waking time daydreaming. “It is a big part of our lives, but it has been largely ignored by science,” she says. “The study is the first to use MRIs to study brain activity during spontaneous thoughts and subjective experiences. Until now the only way is to use self-reports that are not always reliable.”
1. What does the underlined word “they” in Paragraph 2 refer to?| A．Scientists. | B．Scans. | C．MRI machines. | D．Study subjects. |
| A．may help us get relaxed | B．may be beneficial to our health |
| C．may use less energy than focusing | D．may help us arrive at solutions faster |
| A．Daydreaming provides us with many stimuli. |
| B．Daydreaming is actually an act of concentration. |
| C．Daydreaming can make us forget unhappy things. |
| D．Daydreaming reminds us of more useful information. |
| A．MRIs are reliable to study brain activity. |
| B．People should spend more time daydreaming. |
| C．More studies about daydreaming need to be done. |
| D．People should make full use of daydreaming time. |
7 . Thank you, Ma’am
Just an act of kindness changed a boy’s life forever.
She was a large woman with a large purse that had everything in it but a hammer and nails. It had a long strap, and she carried it across her shoulder. It was about eleven o'clock at night, dark and she was walking along, when a boy ran up behind her and tried to seize her purse.
But the boy’s weight and the weight of the purse combined caused him to lose his balance. He fell on his back on the sidewalk and his legs flew up. The large woman simply turned around, reached down, picked the boy up by his shirt front, and shook him until his teeth rattled（发出格格声）.
After that the woman said, “Pick up my pocketbook, boy, and give it here.” She still held him tightly. But she bent down enough to permit him to pick up her purse. Then she said, “Now ain’t you ashamed of yourself?”
By that time two or three people passed, stopped, turned to look, and some stood watching.
She did not release him. “Lady, I’m sorry,” whispered the boy.
“Um-hum! Your face is dirty. Ain’t you got anybody home to tell you to wash your face?”
“No’m” said the boy.
“Then it will get washed this evening,” said the large woman, starting up the street, dragging the frightened boy behind her.
He looked as if he were fourteen or fifteen in tennis shoes and blue jeans.
The woman said, “You ought to be my son. I would teach you right from wrong. Least I can do right now is to wash your face. Are you hungry?”
“No’m,” said the being-dragged boy. “I just want you to turn me loose.”
But the woman continued to drag him up the street. When she got to her door, she dragged the boy inside.
注意：1. 续写词数应为150左右；
2. 请按如下格式在答题卡的相应位置作答。
“Go to that sink and wash your face,” said the women.
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When they had finished eating, she got up and took out ten dollars from the purse.
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8 . “Can you say mama? Or dada?” If you’ve spent any time around a baby, chances are you’ve heard or said things like these.
Baby talk is an important piece of speech and language development. Studies show that when babies are exposed to such talk every day throughout their first year of life, they develop stronger vocabularies than other kids. And the little ones are eager for it.
Child-directed speech wasn’t always valued. Before the middle of the 20th century, researchers largely ignored it as a subject of study. Until the early 1990s, many developmental psychologists and linguists believed that without any help, we would learn how to speak and form complete sentences by ourselves.
But over the past few decades, numerous studies have found that throughout their first year of life, when babies are regularly exposed to such talk in addition to normal speech, they process, learn, and remember words presented to them in singsong tones (语调) better. One reason may have to do with how babies interact with the world.
| A．Baby talk tends to be spoken at a slower rate. |
| B．Humans aren’t the only ones that use baby talk. |
| C．They tend to ignore adult conversations and other background noises. |
| D．Luckily, parents can be taught methods to improve their parentese skills. |
| E．Some doctors even advised parents to avoid using baby talk, thinking it too silly. |
| F．The distinct tone of parentese catches their attention, allowing them to benefit from it. |
| G．The singsong tone we switch to when interacting with young children can have many names. |
9 . The robots are alive, and now they can reproduce.
That’s not a continuation to “The Terminator” It's the latest result of research among scientists at Harvard and the University of Vermont. These xenobots, named for the African frog Xenopus laevis, could move around and display collective behavior.
The researchers took stem cells (干细胞) from the skin of frog and put them in salt water, where they came together into balls with a covering of cilia, which are similar to small hairs and enable the organisms (生物体) to move. The scientists noticed that these organisms, xenobots, would collect any particles (粒子) placed in the dish to make piles. They started to wonder whether the tiny robots would do the same thing with individual stem cells, so they conducted a test.
Knowing that xenobots5 shapes affect their behavior, the researchers tried to figure out which form would help the organism to reproduce repeatedly. They discovered that a “C” shape seemed to be the best. The C-shaped xenobots gathered individual stem cells into groups, which became xenobots of their own. This type of reproduction is based on the organisms’ movement, rather than growing and then forming a new being as other animals and plants do.
Xenobots are on an unusual line between living organisms and robots. They are organisms because they are made of stem cells and can reproduce. But they are also robots because they can move on their own and perform physical labor. Although most robots are made of metal, robots are given the definition not by their material, but by what they can do.
Before now, Kriegman, a postdoctoral fellow at Harvard University, said, “no one has been using living materials as self-moving, self-powered robots.” The researchers hope that the xenobots can help them better understand the process of reproduction —a fundamental quality of life —and how to control it. Faced with a world full of self-reproducing problems, such as Covid-19, Kriegman said studying xenobots could lead scientists closer to solutions.
1. What inspired the researchers to perform an experiment?| A．The position of particles. | B．The gathering of stem cells. |
| C．The movement of organisms. | D．The collective ability of xenobots. |
| A．It's repeated constantly. | B．It generates new beings. |
| C．It separates individual stem cells. | D．It's based on xenobots’ motion. |
| A．By their function. | B．By their reproduction. |
| C．By their unique component. | D．By their physical appearance. |
| A．It could make a breakthrough. | B．It would bring scientists closer. |
| C．It could find the secret of reproduction. | D．It would discover the solution to Covid-19. |
Kareem sighed as he counted his money again. He was still short of fifty dollars to buy the latest Speedster X bike. In order to save his pocket money to replace his old bike, he had been packing sandwiches to school the last three months.
“How can I get that fifty dollars?” he thought to himself. His mind was wondering when Mother’s voice disturbed his thoughts. “Kareem, I just ran into Aunty Kim, our neighbour who just moved in next door. Her son, Shawn, will cycle to school next week. Could you show him the shortcut to school later? It’s Saturday anyway!” Hearing this, Kareem had no option but to obey it, He knew Mother had probably already volunteered his service to Aunty Kim. “Oh, here’s a mail from your Grandma. Open it!” added Mother.
Kareem’s grandmother lived abroad and she would send him photos and cards. He opened the envelope and pulled out a greeting card. Incredibly, a fifty dollar note slipped out as well! Kareem was wild with joy. Waving the note in the air, he shouted happily, “Enough money for my bike!”
At 2 p. m. Kareem met Shawn as arranged by their mothers. The sooner he finished this task, the sooner he could go to the bike shop. While the boys were cycling, a squirrel (松鼠) appeared behind a parked car and dashed across the road so suddenly that the boys knocked into each other and fell down heavily. Kareem said regretfully, “I forgot to warn you about the squirrel population here.” As Kareem was lifting up his broken bike, Shawn cried anxiously, “Oh, my poor bike! It’s completely broken.”
Watching Shawn carrying the disabled bike home in silence, Kareem hurried to the bike shop for his dream bike. The sign “Half Price for Old Models” in the shop attracted his eyes.
注意：
1．续写词数应为150左右；
2．请按如下格式在答题卡的相应位置作答。
“A Speedster X bike or two old models?” Kareem hesitated.
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“Hi!” Kareem appeared at Shawn’s door cheerfully and asked, “Want to ride together?”
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