1 . China's historic 23-day Chang'e 5 mission has not only obtained precious rock and soil samples from the moon, but has also brought back a group of seeds that traveled the furthest in the nation's agricultural and forestry histories. More than 30 kinds of seeds, including that of rice, oats etc., were placed inside the multi-module Chang'e 5 spacecraft and orbited around the moon for about 15 days.
Scientists wished to check what would happen to the seeds after being exposed to extraterrestrial (地外的) forces in lunar orbit and also hoped that they could develop beneficial mutations (突变). This mission offered good opportunities to scientists, which enabled them to deepen their studies on the effect of cosmic rays on the growth and evolution of life on Earth.
Space-based mutation breeding refers to the process of exposing seeds to forces such as microgravity, vacuums and cosmic radiation during a spaceflight and then sending them back to Earth for further observation and planting. Researchers observe and examine several generations of plants grown from space-bred seeds and investigate their mutations-some are positive and desirable while others are negative. Those with positive mutations will be kept and analyzed, and will be introduced to farmers after their certification and approval.
Space breeding can generate mutations faster and more conveniently than ground-based experiments and can bring about some desirable traits that are otherwise hard to introduce. Compared with natural or conventionally bred types of plants, space-developed versions with positive mutations usually feature higher nutritional content, greater annual yields, shorter growth periods and better resistance to diseases and insect pests.
China conducted its first space breeding experiment in 1987, using a satellite to carry seeds into space. Since then, hundreds of kinds of seeds and seedlings have traveled with dozens of Chinese spaceships. Space breeding has helped to produce more than 200 new types of mutated plants in China that have been approved for large-scale cultivation, ranging from grains to vegetables and fruits. The Chang'e 5 robotic mission returned 1,731 grams of lunar rock and soil to Earth, marking a historic accomplishment 44 years after the last lunar substances were taken back.
1. Why were the seeds placed inside Chang'e 5?| A．To pick out the fittest for mutations. | B．To understand extraterrestrial forces. |
| C．To study the intensity of cosmic rays. | D．To expose them to a special environment. |
| A．It is not a time-consuming process. | B．Mutations develop in a random way. |
| C．It often brings about desirable effects. | D．Approval will be granted to mutated plants. |
| A．It is a custom to put seedlings on a spacecraft. |
| B．China was the first to do a space breeding experiment. |
| C．It is some time since seeds were last taken into space. |
| D．Space breeding has brought us commercial benefits. |
| A．Space-bred Seeds Offer Great Chances | B．Chang'e 5 Returns with a Big Package |
| C．Plant Mutations Result in a Better Life | D．Seeds from Space Mark a New History |
2 . Researchers at CU Boulder have developed a wearable device that changes the human body into a biological battery. The device is stretchy(弹性的) enough that you can wear it like a ring, sport band or any other thing that touches your skin. It also taps into a person's natural heat-employing thermoelectric generators to change the body's internal temperature into electricity. "In the future, we want to be able to power your wearable electronics without having to include a battery," said Jianliang Xiao, an associate professor at CU Boulder.
The concept may sound like something out of The Matrix film series, in which a race of robots have enslaved humans to harvest their precious organic energy. Xiao and his colleagues aren't that ambitious: Their devices can generate about 1 volt (伏特) of energy for every square centimeter of skin space-less volt per area than what most existing batteries provide but still enough to power electronics like watches or fitness trackers.
Scientists have previously experimented with similar wearable devices, but Xiao's is stretchy, can heal itself when damaged and is fully recyclable-making it a cleaner alternative to traditional electronics. "Whenever you use a battery, you're depleting(消耗) that battery and will, eventually, need to replace it," Xiao said. "The nice thing about our device is that you can wear it, and it provides you with constant power."
Just pretend that you're out for a jog. As you exercise, your body heats up, and that heat will radiate out to the cool air around you. Xiao's device captures that flow of energy rather than let it go to waste. "The thermoelectric generators are in close contact with the human body, and they can use the heat that would normally be sent into the environment," Xiao said.
1. What does Xiao expect of his device at present?| A．It will be used for medical purposes. |
| B．It will be made smaller and wearable. |
| C．It will change natural power into electricity. |
| D．It will supply constant power to wearable devices. |
| A．To give an explanation. | B．To make a comparison. |
| C．To introduce a topic. | D．To analyze the cause. |
| A．The strengths of Xiao's device. |
| B．The convenience of using a battery. |
| C．The replacement of wearable devices. |
| D．The development of traditional electronics. |
| A．It operates with plenty of power. |
| B．It is designed for practical use. |
| C．It benefits people's health in a way. |
| D．It's based on traditional electronics. |
3 . The kids get Christmas decorations out of a well-loved cardboard box with great care. Jenny stands beside them, softly explaining each treasure. She and Bob built their collection piece by piece during each year's after — Christmas sale.
We first met Bob and Jenny in the early days of our marriage. Someone had been returning our garbage cans to the garage each garbage day. Then one day we spotted him: an elderly man who lived across the street. I left cookies outside the garage with a thank-you note. Later that day, a typed letter had replaced the gift. It was from Bob and explained how he would come to walk the neighborhood on garbage day, returning cans for people he barely knew. Back when he had been fighting a war, his young wife, Jenny, had found herself living alone. Neighbors had taken the time to handle her garbage cans so she didn't have to ...
A few years after we had moved in, Bob died. We told Jenny how special Bob had been to us. When Jenny invited us over to look through Christmas ornaments, I realized how hard it was to part with that box, a piece of Bob.
These days, we're piling up boxes of our own. We're planning a move. The house that seemed so huge six years ago is fully filled with furniture and books and, of course, people. We know it's time to go, and yet we can't seem to stick the For Sale sign up.
It's not just Jenny. It's the man who lets our kids pick peaches in his front yard. It's the ladies who leave overflowing baskets for our kids on Easter. It's the officer who smiles and makes me feel a little safer when Jim's away. Thank you, I'll say. For teaching us what it means to be a neighbor.
1. Why did Bob handle garbage cans for his neighbors?| A．To help those in need of financial aid. |
| B．To repay his neighbors' unselfish help. |
| C．To set an example for the next generation. |
| D．To persuade the neighbors of his greatness. |
| A．Wise and positive. | B．Helpful and caring. |
| C．Hardworking and brave. | D．Grateful and energetic. |
| A．The house isn't big enough for the family. |
| B．There is a better place for the family to live. |
| C．She gets fed up with all the garbage cans. |
| D．Her kids need a better education in the future. |
| A．It is hard to say goodbye | B．How can we leave our home? |
| C．What it means to be a neighbor | D．This is what we call harmony |
4 . A calorie deficit is a state in which you burn more calories than you consume. As one of the most popular approaches of losing weight, how does it work? For example, if you burn 2,500 calories per day but only eat 2,000，you have created a deficit of 500 calories per day. There is mathematical certainty. But, this by no means tells the whole story about how calories deficit affects our lives.
Before wondering what a calorie deficit is, it’s probably best to learn what a calorie is. A calorie is a unit that we use to track our body’s energy expenditure (消耗) and storage. In order to just stay alive, human beings (and animals) burn calories. This means, even before we perform any activity, our bodies are already using energy (measured in calories) to keep us alive. Around 70% of the calories we consume are spent on just keeping our vital organs running. Thus, if a person consumes calories far more less than needed to look thin，it may have negative effects on the body.
When people pick up a calorie deficit, they often merely note that the calorie math is irrefutable (无可辩驳的). The question here is that not all calories are the same. If you eat a few bags of potato chip worth of calories to support the calorie intake needed to maintain or cut down on your weight, it will work. But, this doesn’t have the same effect on your body and overall health as a balanced nutritional meal containing the same amount of calories.
It seems like a simple unit of energy has become an object of our society’s obsession. It needn't be that way. Remember, calorie deficits are just a tool, which serves a purpose in losing some weight and keeping track of your calorie intake seems simple enough.
1. What do we know about the calorie deficit?| A．It helps people lose weight. |
| B．It is a way of doing exercises. |
| C．It affects people's lives positively. |
| D．It means the calories people consume. |
| A．A calorie is a unit to store daily energy. |
| B．People need to burn calories to be alive. |
| C．Calorie intake is to keep our organs operating. |
| D．Living animals only burn calories after activities. |
| A．Focusing on the calorie math when eating. |
| B．Focusing on different calories when eating. |
| C．Having bags of potato chips containing enough calories. |
| D．Having balanced nutritional diets containing proper calories. |
| A．Influences of calorie deficits. | B．Approaches to lose weight. |
| C．Distinctions between calories. | D．Ways to track calorie intake. |
5 . The popularity of Chinese-owned video-sharing service TikTok(抖音)continues to grow among young people in the United States. In 2019, experts say the service more than doubled its American user base to 37 million. TikTok is especially popular with teens and young adults.
The service lets users create and share their short videos that they think interesting and useful. Many of them are under 15 seconds. The TikTok app offers a wide choice of sounds, brief parts of songs and special effects tools to help create a video. Some TikTok-based memes(表情包)are very popular. Videos often include popular songs from well-known artists and TikTok has even helped launch the careers of new music stars.
TikTok is considered a competitor to the video-sharing app Snapchat, as well as Facebook's Instagram service. Snapchat and Instagram also mainly interest young users with a wide mix of photos and videos centered largely on fashion, pop culture and humor.
Last year, TikTok was the second-most downloaded app from Apple and Google stores. Only WhatsApp was downloaded more. Research company Sensor Tower guesses people have downloaded the TikTok app 1.65 billion times.
TikTok has been used by many major companies to reach young people who use little or no traditional media. One of those companies is American-based e. l. f. Cosmetics(化妆品). The makeup company's chief marketer, Kory Marchisotto, said that TikTok is "where the Gen Z party is". Gen Z is a name used to call the generation born between the late 1990s and the early 2000s.“That's where they're all hanging out," Marchisotto said.
Companies appearing on TikTok can make money through advertising. Often, the companies create user "challenges" as part of their advertisement campaigns. TikTok users created 3 million videos that received more than 4 billion view.
1. Which word can best describe the videos created on TikTok?| A．Traditional. | B．Boring. | C．Various. | D．Serious. |
| A．TikTok. | B．Snapchat. | C．Instagram. | D．WhatsApp. |
| A．Challenge their competitors. | B．Make advertisements. |
| C．Hold music concerts. | D．Promote users' abilities to make videos. |
| A．TikTok Keeps Growing Among US Youth | B．How to Share Short Videos |
| C．Facebook Achieves Great Success | D．Companies Benefit Much from Videos |
6 . This year, new technologies will enable more drivers to take their hands off the steering wheel （方向盘）while on the road. But that doesn’t mean their cars will be fully self-driving --- that day still remains far in the future.
Automakers like General Motors （GM）, Ford and Stellantis are introducing, or upgrading existing technologies. But in the words of Kay Stepper, an automated driving expert, these systems are "feet off’ and "hands off’, but they will not be "eyes off" or “mind off’.
For the time being, these systems will only be used on limited-access highways, where there are no pedestrians or bicyclists. Vehicles with this technology will be able to drive at relatively high speeds, but only in simple traffic situations.
Bryan Reimer, a researcher with the Massachusetts Institute of Technology’s AgeLab, said it will be decades before people can buy truly self-driving cars in which humans ride as passengers.
Still, the technology that will be rolled out by the major automakers this year will do more than most so-called Advanced Driver Assistance Systems, or ADAS, do now.
GM’s Super Cruise system allows drivers to completely let go of the steering wheel while driving on selected highways. It was introduced in 2017 on the Cadillac CT6 sedan, which was discontinued last year. An improved version is coming this year on the Cadillac Escalade SUV and the Cadillac CT4 and CT5 sedans.
Super Cruise only works on highways that have been previously laser-mapped in three dimensions. GPS positioning and the vehicles, radar sensors （传感器）and cameras are used to enable drivers to unhand -- and unfoot — all the controls.
Drivers still need to pay attention, however. A camera in the car makes sure the driver is looking at the road at all times. If the driver looks away from the road for more than a few seconds, the system will stop working.
1. At present, what can the self-driving cars do?| A．They can drive freely on city streets. |
| B．They can run without human drivers. |
| C．They handle complex road conditions on their own. |
| D．They allow drivers to take their hands off the steering wheel. |
| A．GM’s Super Cruise system. | B．GM’s latest car models. |
| C．GM’s development plan. | D．GM’s close competitors. |
| A．People need to trust new technology. |
| B．People still need to pay attention. |
| C．People can look away from the road. |
| D．People can’t unhand all the controls. |
| A．It’s High Time to Get a New Car |
| B．The Industrial Revolution Is Underway |
| C．Super Cruise Does More than Most ADAS |
| D．The Real Self-driving Remains Far Away |
7 . Some termite (白蚁) species have figured out how to enjoy the shelter of the huge complex nests that the insects build without contributing to their construction. They avoid the full anger of their builder hosts by being extremely easy-going.
Animals that live in the nests of another species without affecting them are known as inquilines. Inquiline termites are unique among termites in being unable to make their own nests. Instead, they live in the hallways built by another termite, Constrictotermes cyphergaster. Until now, it has been unclear how the two parties kept peaceful in such tight quarters because termites are typically very aggressive towards outsiders.
Helder Hugo at the University of Konstanz in Germany and his colleagues collected Constrictotermes cyphergaster’s nests in the Brazilian Cerrado and brought them into the laboratory. They then placed host and tenant (房客) termites in either open or narrow areas and used video to track and record the ways in which the two species reacted to each other.
Right from the start, the inquiline’ termites moved around less than their hosts and interacted little with them, even in the much narrower area. “Many times,” says Hugo, “when two unrelated groups are put together in a limited space—such as an experimental area—the outcome is conflict with losses from both sides.” But that didn’t happen here. Despite attacks from host termites, the tenant termites were obedient. Hosts would bite or attack the inquilines with strong chemicals, but their targets never responded in the same way, choosing to flee. Some ignored the hosts completely.
“We did not expect that they would never fight back,” says Hugo, noting that the inquilines are capable of protecting their own place with mouths. “By preventing conflict going worse, inquiline termites may considerably improve their chances of living together with their host termites peacefully.”
“Passiveness does not necessarily lead to defeat, but can be a very useful strategy, saving energy and resources,” she adds. “Nature may not always be red in tooth and claw, and aggression is not any more successful a strategy than ‘cowardice’ (儒弱).”
1. What is the feature of the inquiline termites?| A．They live in another termite species’ nests. |
| B．They are aggressive towards outsiders. |
| C．They like to build their own nests. |
| D．They are communicative tenants. |
| A．The differences between the two species. |
| B．The findings of the observation. |
| C．The living habits of termites. |
| D．The process of the research. |
| A．Aggressive. | B．Unacceptable. | C．Effective. | D．Dangerous. |
| A．The Characteristics of Termites |
| B．Passiveness Doesn’t Necessarily Lead to Defeat |
| C．The Relationship Between Host and Tenant Termites |
| D．Termites Use Cowardice to Avoid Their Hosts’ Anger |
8 . Yawning is something we all do -- maybe because we're bored carrying out boring tasks or because we're tired. Sometimes, just seeing other people yawn can set you off. But is this biological function really contagious, and why do we do it in the first place?
Many of us think we open our mouths when we yawn to take in more oxygen, but in fact it appears there is no clear biological reason. According to BBC Bitesize, new research suggests it might be because yawning cools the brain down and prevents it from overheating, much like the fan in your laptop. This might be why we're more likely to feel sleepy and yawn in warm temperatures.
What is clear is that we yawn more when we're exhausted and ready for a nap, and we can't control when we do it -- once we start, there's no stopping us! But it's also true that yawning is a very contagious behavior. John Drury, a researcher from Sussex University found in his research that there is a connection with our social group and how close we are to the people in it. If we identify with the person who exhibits the behavior, we are likely to copy it too.
Another research by the University of Nottingham in 2017 found similar results. They asked volunteers to watch other people yawn. They found their ability to resist yawning when others around them yawned was limited. And the urge to yawn was increased when people were told they couldn't. They also found, when using electrical stimulation, that they were able to increase people's desire to yawn. These findings, they say, could be useful in treating other conditions like Tourette's, which involve the same area of the brain.
What is certain is that a yawn can creep up on us at any time even when we think we're not tired --but, I hope, not when you're reading this article!
1. Which of the following is the closest in meaning to the underlined word “contagious”？| A．Infectious. |
| B．Active. |
| C．Dangerous. |
| D．Efficient. |
| A．we are too exhausted. |
| B．our brain needs more oxygen. |
| C．we are bored with difficult tasks. |
| D．our brain needs to be cooled down. |
| A．Humans can't stop yawning as it is beneficial. |
| B．When told not to yawn, we will yawn less frequently. |
| C．Using electrical stimulation can stimulate people to yawn. |
| D．We are more likely to yawn when someone around us yawns. |
| A．The reasons for yawning. |
| B．The benefits of studying yawning. |
| C．The necessity of yawning. |
| D．The similarity of the studies on yawning. |
9 . "Carers" are all sorts of people with so many different caring roles. I know this only too well from attending my severely ill mother as a teenager, to having main carer responsibility for my Nanna for her last ten years, to now as a father caring for my disabled son.
But more importantly, I was also cared for. My dad had died when I was four, so after my mum died, it was my amazing Nanna and Grandad who took me in. Because they were my grandparents, I never really thought of them as "carers"，and I don't think they did either. Back then, I probably didn9t even know what 66kinship（亲属关系）carer" meant
It wasn't easy for them. My mother's long illness and early death nearly broke them. I used to think looking after me helped them deal with their heartbreak. But the truth is, they helped me get over my mum's death. Surrounding me with unquestioning love, they were classic kinship carers.
Working as a lawyer, I've helped a surprisingly large number of kinship carers over the years—mostly grandparents, fighting the system for their precious grandchildren. I like to think I go the extra mile, which helped them face the challenges. More than 180,000 children across the UK are being raised by kinship carers today, but the huge challenges facing them are too often forgotten by politicians and policymakers.
What my Nanna and Grandad did—and what kinship carers across the UK are doing today—is amazing. They are giving a loving home to these children, while reducing the stress on the formal care system― ven though it may add difficulties to their own life. We can't thank and support them too much.
1. The author knows very well about what carers are by .| A．giving and getting care | B．doing voluntary work |
| C．becoming a parent | D．learning from carers |
| A．They took care of the author's ill mother. |
| B．They spoiled the author with too much love. |
| C．They offered to look after the author's children. |
| D．They helped the author get through hard times. |
| A．Take the wrong way. | B．Make a special effort. |
| C．Save much precious time. | D．Do some unnecessary work. |
| A．Carers Face Huge Challenges |
| B．More Kinship Carers Needed |
| C．Carers Deserve Recognition and Support |
| D．British Policies Intended for Kinship Carers |
10 . The practice of drinking tea has a long history in China. According to a popular story. tea was discovered by Shennong in 2737 BC when a leaf from a nearby shrub（灌木）fell into the water Shennong was boiling. Tea is deeply woven into the history and culture of China.
The Chinese have a saying: “Firewood, rice, oil, salt, sauce, vinegar and tea are the seven necessities to begin a day.” Though tea is the last on the list, we still can see its importance in daily life. A simple meal in Chinese is Cu Cha Dan Fan, which shows even a simple meal is finished with tea.
For the Chinese, tea drinking and tasting are not parallel. Tea drinking can help keep up one’s spirit while tea tasting has cultural meaning. Tea and tea sets should match the breeze, the bright moon, bamboo and so on. All these show the goal of Chinese culture: the harmonious（和谐的）unity of human beings with nature.
Similarly, tea-drinking habits differ in different parts of China. Generally. flowering tea is popular in northern China; green tea is preferred in eastern China, and black tea is fit for people in Fujian and Guangdong. Green tea is the most popular type of tea drunk in China. Green tea usually loses its flavor（味道）within a year while the flavor of black tea can remain for several years. As a result, black tea has long been traded worldwide. It still accounts for over ninety percent of all tea sold in the West. At present, tea is commonly seen in Chinese restaurants and grocery shops worldwide.
1. Why does the author use the Chinese saying in Paragraph 2?| A．To show the tea’s role in Chinese culture. |
| B．To express the author’s love for tea. |
| C．To show the history of tea. |
| D．To explain the Chinese saying. |
| A．Different. | B．Strange. | C．Ordinary. | D．Equal. |
| A．It suits people in Fujian and Guangdong. |
| B．It tastes better than green tea. |
| C．Its flavor can be kept for a long time. |
| D．Its flavor is preferred by the West. |
| A．The development of tea drinking in China. | B．The culture of tea in China. |
| C．The popularity of tea drinking in China. | D．The history of tea in China. |
